This is a mix of your usual evasion, omission, and confusion, coupled with some downright silly stuff. I'm only going to bother answering some of the points.

How would Newman's being in "close proximity" to the headshot have caused Newman to hear a bullet whiz by him from behind? Newman was 15 feet from the limo at Z313 and the limo was to his left front. So do tell me how a bullet traveling from the sixth-floor window and hitting JFK's head 15 feet away to Newman's left front would have caused him to hear a bullet whiz by him from behind. You realize that Newman was so certain that gunfire was coming from behind him that he dropped down to the ground, right?

Oh, yes, Zapruder most certainly did categorically tell the SS that the gunman was positioned behind him. He expressed no qualification or uncertainty whatsoever, nor did he say that this was merely his "impression." He only started to waffle about the gunman's location later on.

So three cars doing an obvious recon in the parking lot behind the knoll in the 25 minutes leading up to the shooting, after the area had been sealed off by police, and with one of the drivers talking into a microphone -- nah, that's not suspicious at all, huh? Yeah, okay. You'll never admit anything if it contradicts the lone-gunman myth.

Show me where in Lee Bowers' WC testimony he said he did not see a gunman behind the fence. Give me the page number. His testimony is in 6 H 284-289. Where does he say he didn't see a gunman behind the fence?

Lee Bowers told Mark Lane there was no one behind the fence at the time of the shooting:

"Now I could see back or the South side of the wooden fence in the area, so that obviously that there was no one there who could have, uh - had anything to do with either - as accomplice or anything else because there was no one there, um, at the moment the shots were fired."

He also said he heard three shots. Not four. Or five. And they all came from either end of Elm Street; either by the Depository or "the mouth of the triple underpass". He wasn't sure. Three shots. All from one location.

This key witness you are promoting completely demolishes your conspiracy.

Link: https://www.jfk-assassination.net/pdf/lane_interviews/bowers.pdf

This is a mix of your usual evasion, omission, and confusion, coupled with some downright silly stuff. I'm only going to bother answering some of the points.

And ignore the ones for which you have no rebuttal.

How would Newman's being in "close proximity" to the headshot have caused Newman to hear a bullet whiz by him from behind? Newman was 15 feet from the limo at Z313 and the limo was to his left front. So do tell me how a bullet traveling from the sixth-floor window and hitting JFK's head 15 feet away to Newman's left front would have caused him to hear a bullet whiz by him from behind. You realize that Newman was so certain that gunfire was coming from behind him that he dropped down to the ground, right?

Do you really think Newman could tell whether or not a bullet had whizzed past him? I don't doubt he could hear a bullet, probably the headshot. How could he tell if that bullet had gone past him or simply gone near him. We are talking about an event that would have lasted one or two MILLISECONDS? Are we supposed to believe he could lock in on where that bullet was in that brief a time span?

Oh, yes, Zapruder most certainly did categorically tell the SS that the gunman was positioned behind him. He expressed no qualification or uncertainty whatsoever, nor did he say that this was merely his "impression." He only started to waffle about the gunman's location later on.

Why is it you never quote the people you cite but instead choose to put your spin on what they said. Let me show you how you quote someone. First, you find the source for the person you have quoted. In this case, I am quoting Zapruder's WC testimony from this webpage:
https://www.jfk-assassination.net/russ/testimony/zapruder.htm

Then you find the passage you want to quote and highlight it. On my laptop, the passage will turn to blue. Then you right click it and select COPY from the pull down menu. Then you go to where you are typing your post and type in a double quotation mark and right click again. Then you select PASTE from the pull down menu and OUILA! The passage you want to quote appears after the quotation mark. Then you type in another quotation mark to close the quote, and it looks something like this:

"Mr. LIEBELER - Did you have any impression as to the direction from which these shots came?
Mr. ZAPRUDER - No, I also thought it came from back of me. Of course, you can't tell when something is in line it could come from anywhere, but being I was here and he was hit on this line and he was hit right in the head--I saw it right around here, so it looked like it came from here and it could come from there."

That doesn't sound to me like Zapruder was categorically saying the gunman was behind him.

So three cars doing an obvious recon in the parking lot behind the knoll in the 25 minutes leading up to the shooting, after the area had been sealed off by police, and with one of the drivers talking into a microphone -- nah, that's not suspicious at all, huh? Yeah, okay. You'll never admit anything if it contradicts the lone-gunman myth.

You do this all the time. You claim that those cars patrolling the parking lot were suspicious and then shift the burden to me to disprove it was suspicious. If you think these cars had a sinister motive, the burden is on you to establish that, but since you have no evidence, you simply assume something you can't prove. You also lack the common sense to ask yourself a very simply question. If that parking lot had been sealed off as you claim, the only way those cars could have gotten in is if the people guarding the entrance let them in which would indicate they had clearance to enter. It is not surprising they would want to do several checks of that area to make sure someone hadn't entered that parking lot covertly. But that explanation is too boring for you typical CT. They want to assume every unexplained event has sinister connotations.

Show me where in Lee Bowers' WC testimony he said he did not see a gunman behind the fence. Give me the page number. His testimony is in 6 H 284-289. Where does he say he didn't see a gunman behind the fence?

The pages are not numbered. The source of this quote is:
https://www.jfk-assassination.net/russ/testimony/bowers.htm

This is how Bowers described the shooting:

"Mr. BALL - When you heard the sound, which way were you looking?
Mr. BOWERS - At the moment I heard the sound, I was looking directly towards the area---at the moment of the first shot, as close as my recollection serves, the car was out of sight behind this decorative masonry wall in the area.
Mr. BALL - And when you heard the second and third shot, could you see the car?
Mr. BOWERS - No; at the moment of the shots, I could---I do not think that it was in sight. It came in sight immediately following the last shot.
Mr. BALL - Did you see any activity in this high ground above El after the shot?
Mr. BOWERS - At the time of the shooting there seemed to be some commotion, and immediately following there was a motorcycle policeman who shot nearly all of the way to the top of the incline."

BTW, do you know who Walter Rischel and James Sterling were? They were friends of Lee Bowers. Sterling gave a statement to New Orleans DA investigator Gary Sanders that Bowers told him that after the shots were fired, he saw two men running from behind the fence, that they ran up to a car, threw something in the trunk, jumped in the car, and drove off. Rischel stated in a filmed interview that Bowers did not tell the WC everything he saw. Also, Bowers' wife told journalist Penn Jones, on the record, that Bowers was warned "not to talk."

Nice of you to fill us in on the rumors. Once again, you fail to provide a quote except for a three word phrase taken out of context. WTG!!!

Of course you denounce Ed Hoffman, but we both know you have not read any of the research that supports Hoffman's account and veracity. This is typical of your blind bias and automatic and uninformed rejection of any and all evidence that you don't like.

The fact you would cite Ed Hoffman reveals how desperate you are to make a case for a gunman on the GK. It also tells everyone that you aren't somebody who should be taken seriously.

Your comments about Charles Whitman's rifle skills and your attempt to infer from them that Oswald could have performed the alleged lone-gunman shooting feat are truly hilarious, not to mention discrediting.

How so? Do you think those 2 extra points Whitman scored above what Oswald did indicated he was a vastly superior marksman? Do you think someone who ONLY scored 212 in USMC would be incapable of shooting a man twice in three shots from ranges of 88 yards or less but someone with a score of 214 would be more than capable of killing 11 people and wounding 34 more from a height more than twice what Oswald was at and at far greater distances? One of Whitman's kill shots was estimated to be from 500 yards.

If I could read minds, I would genuinely be curious to know how you rationalize in your own mind the fact (1) that none of the WC's three Master-rated riflemen even came close to duplicating Oswald's alleged shooting feat, even though they were firing from only 30 feet up and were shooting at stationary target boards, and (2) that out of the 12 riflemen in the 1967 CBS rifle test, all of whom were experienced riflemen and six of whom were experts, only one of them (one of the experts) seemingly duplicated the supposed shooting feat and only because the test counted as "hits" shots that landed well outside the target area that Oswald allegedly hit (the test actually tripled the size of the target area).

The CBS marksman were expected to fire three shots in 5.6 seconds or less. Oswald was under no such constraint. The fact is the only two recovered bullets from the shooting were positively matched to the rifle found on the 6th floor. Oswald's rifle. With fibers matching the shirt he was wearing on the butt plate of the rifle. That indicates somebody performed the shooting feat from the sniper's nest and there is plenty of evidence that indicates that somebody was Oswald. That makes it rather silly to claim that neither Oswald nor his rifle were good enough to have made those shots.

Yes, there most certainly is hard evidence of a gunman on the grassy knoll: the HSCA's scientific acoustical identification of a shot fired from the knoll, the puff of smoke visible in the Wiegman film near the same area where six witnesses said they saw gun smoke, the optical-density measurements that prove the skull x-rays indicate missing occipital bone, the identification by several medical experts of an entry wound in the right temple on the skull x-rays, mortician Tom Robinson's description of a small wound in the right temple (he examined it and filled it with wax to keep it from leaking), the Harper fragment, and the powerful spraying of blood and brain matter backward onto the two left-riding patrolmen and the follow-up car.

Missing occipital bone is not hard evidence of a shot from the GK. The upper right side of JFK's skull was blown out, mostly parietal bone but also involved the occipital and temporal regions. Frame Z313 indicates the spray of blood and brain from JFK's head went forward and upward, a fact you simply want to ignore, just as you ignore the fact the motorcycle escorts were moving forward drove through that red cloud. There was a small amount of discharge to the rear but most of it went forward.

One, a number of the witnesses who said they heard gunfire from the grassy knoll also said they heard gunfire from the TSBD as well.

Only a handful of witnesses thought the shots came from more than one place. Most witnesses thought it was one or the other. 

Two, the powerful sound-wave reverberations from the knoll's pergola alone could have easily caused some witnesses to believe that two or three shots were fired from the knoll.

Do you not think Oswald's shots from the sniper's nest could have reverberated and caused people to believe two or three shots were fired from the knoll?

Finally, I have yet to see you deal with the fact that even after introducing two brazen errors into their recalculation of the probability of the grassy knoll shot, the NRC/NAS panel was still only able to reduce the probability to 77.7%. No one denies the panel's two severe errors, and subsequent research has shown that the probability of the grassy knoll shot is actually virtually 100% (vs. the Weiss-Aschkenasy calculation of "95% or higher").

When statistics experts describe a probability of 77.7%, they use such terms as "likely" and "probable," whereas they describe a probability of 60% as "moderately likely" and "moderately probable." A probability of 77.7% is only 2.3 percentage points from qualifying as "highly likely" in a probability perception scale (https://waf.cs.illinois.edu/visualizations/Perception-of-Probability-Words/).

A "95%" probability is considered to mean "almost certain." Legal sources note that a 95% probability is often estimated by judges and legal experts to match the threshold of "beyond a reasonable doubt," as Dr. Weiss noted in his HSCA testimony. And, again, subsequent research has found that the grassy knoll shot's probability is actually virtually 100%, like 98% and above.

President Hillary Clinton could tell you about the value of assumed probabilities.

Junk science is still junk science. They can claim all the probabilities they choose. It doesn't make their conclusions more compelling. You try to make it sound like there is a consensus that the acoustic evidence was a recording of the actual shooting. Below is a summary of the dissenters:

Reasons for Doubting the Acoustic Evidence of a Grassy Knoll Shot
Several independent scientific reviews and later analyses have raised serious doubts about the conclusion that the Dallas Police Department dictabelt recording contained a gunshot from the grassy knoll.

1. Timing and simultaneity issues
The National Research Council’s Committee on Ballistic Acoustics found that the putative gunshot impulses on the dictabelt were recorded about one minute after the actual shooting, not contemporaneously
. If the impulses were not captured at the same time as the shots, they could not reliably indicate where the shots originated.

2. Methodological limitations
The original Bolt, Beranek & Newman (BBN) and Weiss & Aschkenasy analyses relied on echo-correlation and acoustic modeling that compared dictabelt impulses to test shots fired in Dealey Plaza
. Critics noted that these methods assumed ideal conditions (e.g., perfect microphone placement, no background noise) that were not met in reality, and that the statistical confidence levels (e.g., “95% probability”) were based on models rather than direct forensic measurement

3. Recording and transmission problems
The dictabelt was a routine police radio recording, not set up to capture gunfire. A motorcycle on channel I had a defective microphone button that caused continuous transmission for several minutes, potentially distorting or masking sounds
. This raised questions about whether the recorded impulses were genuine gunshot signatures or artifacts.

4. Lack of corroborating evidence
No other physical or eyewitness evidence confirmed a second shooter from the grassy knoll. The acoustic conclusion was the sole “scientific” basis for the HSCA’s conspiracy finding, and later reviews found no independent verification of the claimed impulses

5. Replication and peer review disputes
The National Academy of Sciences and other peer-reviewed studies concluded the original findings were not supported by the data, while some later researchers (e.g., Donald B. Thomas) disputed the timing critique and defended the original results
. This split in the expert community reflects unresolved methodological and interpretive disagreements.

In summary:
Doubts center on the recording’s reliability, the timing of the impulses, the assumptions in the acoustic models, and the absence of corroborating evidence. These issues led the National Research Council and other independent bodies to question whether the acoustic evidence could validly establish a shot from the grassy knoll

I'm sure readers have noticed that WC apologists, as evidenced by Tim Nickerson's labored and errant replies, still have not been able to explain the fact that the back-wound bullet could not have come from the sixth-floor window unless JFK had been leaning markedly forward when the missile struck, and that no photo or frame shows JFK's head tilted anywhere near that far forward, if at all.

Incredibly, Nickerson can't even admit what the HSCA's SBT diagram plainly shows, and he's still erroneously denying that Rydberg drew CE 385 under Humes's direct and point-by-point supervision, even though Humes and Rydberg themselves made this clear. I find it amazing that Nickerson actually cites Humes's descriptions of the back wound to support the claim that the wound was in the neck and not in the back, never mind the bullet holes in the rear of JFK's clothing, never mind the autopsy photo of the back wound, never mind the autopsy face sheet, never mind the "certified" death certificate, and never mind the HSCA FPP's SBT diagram. I see Nickerson even resorts to the ridiculous bunched-clothing theory, ignoring the fact that no photo or frame shows the jacket bunched nearly enough to make the holes align with a wound several inches higher, and ignoring the fact that Willis slide 5, taken much closer to the moment of impact, shows the jacket virtually flat on JFK's back.

This thread is a great example of the fact that WC apologists have largely ignored the HSCA FPP's findings about the back wound's location (slightly below the throat wound or, at the most, level with it) and the bullet's upward trajectory. In their various and conflicting SBT diagrams/animations, WC defenders always (1) have JFK sitting upright with his head held upright or tilted only slightly forward, (2) have the bullet traveling downward through the neck.

It is worth remembering that Dr. Werner Spitz, a prominent forensic pathologist who served on the RC's medical panel and on the HSCA FPP, informed the RC in 1975 that there was "no doubt" that the back-wound bullet hit the back "in a sharply upward direction" and that it traveled "upwards within the body":

There is no doubt that the bullet which struck the President’s back penetrated the skin in a sharply upward direction, as is evident from the width of the abrasion at the lower half of the bullet wound of entrance. The term "sharply upward direction" is used because it is evident from this injury that the missile traveled upwards within the body. (Report of Werner Spitz, 4/24/75, p. 1, Rockefeller Commission papers)

Spitz was either unaware that these facts destroyed the SBT or he dismissed as irrelevant all the photos and footage taken of JFK during the SBT's timeframe. Ditto for Dr. Baden when he demonstrated in the 1988 NOVA JFKA documentary that the alleged magic bullet's trajectory would have been upward through the neck and that this trajectory could only align with the sixth-floor window if JFK had been leaning markedly forward when the bullet struck.

The Clark Panel measured the entry wound to be 5.5 cm below that transverse fold in the skin of the neck. The HSCA's FPP measured it to be 6 cm below the skin fold. Going but what you see in that photo above, place a mark on the back in the lateral view below at the level that you believe that the wound was at. The yellow line represents my own determination of the approximate wound entry level and subsequent downward path of the bullet to the throat wound. The photo is not a diagram or an animation. It's an actual photograph of the body of Kennedy.

I think the First shot might've been fired around the same time as the first splice on the Zapruder film

What “splice” are you referring to?

What, are you gonna try to convince me the first shot was fired after Kennedy starts waving again?

Do you mean after he began waving for the last time, which, as Mary Woodward said, was before the first  “horrible, ear-shattering noise”? And after Betzner’s z186 photo, which he said was just before the first shot? And after the VP car completed the turn as all its occupants said? (the VP car is almost finished turning at z180 when last seen in the zfilm).

After the little girl in the background stops running?

Rosemary Willis said she stopped when she heard the first shot. Her feet stopped at z199.  The first shot was not after that, according to her.

After Connally turns around?

He turns “around” only once - z230-270. The first shot was before that.

Since it is obvious that lone-gunman theorists here are simply not going to admit that the HSCA FPP's SBT actually destroys the SBT, let us take a moment to revisit the fact that there were too many bullet fragments deposited in Connally's body to have come from CE 399, the SBT's alleged bullet.

In his 11/29/63 supplemental x-ray report on Connally's wounds, Dr. Jack Reynolds, Parkland Hospital's chief radiologist and later a professor or radiology at Southwestern Medical School, said the metal fragment in Connally's thigh measured approximately 3.5 mm x 1.3 mm on the AP x-ray and about 2.0 mm x 1.5 mm on the lateral x-ray, so it was definitely somewhat dense and not any kind of a "flake":

There is, however, one density which remains constant on both films and appears to lie beneath the skin of the region of the subcutaneous fat in the medial aspect of the thigh meters posterior to the exterior of the anterior cortex. The shape of this density is irregular but is roughly oval. Precise measurements are difficult but it is estimated that the greatest length in the AP projection is about 3.5 millimeters and the greatest width about 1.3 millimeters.

Measurements of the densities in the lateral projection reveal the greatest length to be about 2 millimeters and the greatest width to be about 1.5 millimeters The long axis of the metallic object is oriented generally along the axis of the femur. ("Supplemental Report Describing in Detail the Appearance and Location of a Small Metallic Density Superimposed on the Soft Tissue Shadows of the Medial Aspect of the Left Thigh of Governor John Connally on Films Dated November 22, 1963," 11/29/63, pp. 1-2)

In his 11/9/77 HSCA interview, Dr. Reynolds said the identifiable opacity in the thigh x-rays "definitely has metal characteristics" and that his 11/29/63 report describing "the location of this fragment" was "correct":

Dr. Reynolds stated that an identifiable opacity exists in the thigh x-rays and that it definitely has metal characteristics. He stated that his 11-29-62 report, describing the location of this fragment as just beneath the skin in the region of the subcutaneous fat, is correct. (7 HSCA 320)

In addition, Dr. Reynolds said there were "at least" four bullet fragments visible in Connally's wrist wound:

After examining the original and the enhanced x-rays, Dr . Reynolds stated that there are at least four fragments of metal identifiable in Gov. Connally's wrist wound (7 HSCA 320)

The wrist fragments and the thigh fragment could not have come from CE 399, given that the bullet was missing less than 4 grains of its substance. Russell Kent:
 
Dr. Gregory, Professor of Orthopedic Surgery, testified that he removed two fragments (but left other small fragments in the wound). These became Warren Commission Exhibit (CE) 842 below in Figure 32. There is no explanation of how the two fragments became four.

On 29th November 1963, Parkland Memorial Hospital sent Connally’s x-rays to the FBI. The dimensions of the fragment left in his thigh, as shown on one of the x-rays, were 3.5 mm by 1.3 mm.     

These are quite large fragments. It is reasonable to doubt that these fragments came from CE 399. (JFK Medical Betrayal: Where the Evidence Lies, pp. 210-211).

As I've pointed out previously, before they knew what they were supposed to say, before the SBT emerged as the explanation for JFK and Connally's non-fatal wounds, even Dr. Humes and Dr. Finck said that Dr. Gregory's 11/22/63 operative report described too many bullet fragments to have from CE 399 (2 H 374-375; 2 H 382).

This is why amateurs such as yourself should not try to analyze evidence that calls for expertise. You compare dimensions of the flakes to the weight of CE399. Talk about apples and oranges. The surgeon who removed the flakes from JBC's wrist estimated they had the weight of a postage stamp.