Tyler's take on the shots is quite flawed. He calls an early missed shot a red herring. He has three shot bursts. Shot Burst 1 (Z180-Z40)is made up of two shots. He has the first one missing at Z185 and Kennedy and Connally being hit by the other at about Z220. Shot Burst 2 (Z270-Z330) contains only one shot; the head shot. He says that if the shot was fired from the sixth floor window of the TSBD it would have been fired at Z310. For Shot Burst 3 (Z360-Z420), it's not clear if he favors one or two shots.
I think you may have misread what he is saying (or maybe I am). Perhaps he should be invited to clarify his thinking here? (In fact, I'm going to do that right now.)
What I liked about his Technical Reference Manual is that it is both comprehensive and non-dogmatic.
The red herring (in his opinion) that he dismisses is: "A common red herring is where writers discuss a missed shot before Z180, and then within a few seconds a second shot around Z210-Z220."
FWIW, these are the points he says he is "certain" about. ("Bursts" does not mean he thinks more than one shot was necessarily fired in each such "burst." It's his way of dealing with the evidence in a non-dogmatic way.)
• Only three bursts of gunfire were fired in Dealey Plaza because no witness heard a fourth burst.
• Any witness who heard more than three shots grouped two or more shots together within just one burst (such as two shots fired within a second).
• The Zapruder film identifies when two of these bursts were fired due to the reactions of the victims at Z225 and Z313, which means the sound of gun fire reverberated around Dealey Plaza at those points in time.
• The first gunshot fired was after Z180 and became audible to the witnesses soon after. Most witnesses close to the Presidential limo associate this burst of noise with JFK’s reaction we see after Z225 of the Zapruder film.
• The third burst of gunfire was fired some seconds after Z313, probably aroundZ360-Z400, because so many witnesses heard a shot or shots fired well after Z313.
• A sniper was located in the sixth floor window of the TSBD who fired three shots, as reported by a number of witnesses including Amos Euins, Howard Brennan, and Harold Norman.