I answered all of that a long time ago.
The timings from Lattimer's tests for lapel flip indicates a shot at z219.
But i hav pointed out that the design of Lattimer's test jacket (hiz jacket had a long lapel) & the pozzy of Lattimer's shot (he shot higher than in 1963)(& hiz slug hit hiz 1994 lapel & took a big chunk out of it) indicates that the shot woz at Z218, which iz what i hav sayd all along.
I find it interesting that Lattimer tested that. I've long hypothesized that there could be a brief time lag between the single bullet passing through JFK and JBC and JBC's jacket bulging out and wished that somebody would test that hypothesis. Now you are saying that had been done. I am surprised at how much lag time you and Lattimer believe there was, but I don't dispute it.
I don't think we can assign precision to these tests because of the variables. Did Lattimer fire a shot directly through the jacket? If so, it would be pristine and meet much less resistance by the jacket as it passed through the material. The single bullet was not pristine as it exited JFK's throat. It began yawing immediately and based on the shape of the entrance wound on JBC's back, the axis of the bullet would have been almost perpendicular to the flight. It likely would have had a similar orientation when passing through the front of JBC's jacket. A pristine bullet, i.e. one that is not yawing, is going to meet little resistance when passing through a soft object. I have shot empty aluminum cans with my .44 Magnum and they don't even budge. My layman's opinion is that the more yaw, the more resistance a bullet will be met with. The more resistance, the quicker we would expect to see the jacket bulge. Again, this is my hypothesis, but I lack the means to test it out.
To me, the best indication of the time each shot was fired is the jiggle we see in Zapruder's film following each shot. Because the distance from Oswald's rifle to Zapruder's ears was a constant for all three shots, we should expect a similar time lag between shot and jiggle for all three shots. Let's start with the third shot since that is the easiest to pinpoint. A bullet striking JFK's head at Z313 would have taken about 2 frames to travel the 88 yards from Oswald to JFK. That would mean the shot was fired at Z311, followed by a severely blurred frame at Z318. That gives us a baseline of 7 frames between the shot being fired and Zapruder's involuntary response. If we apply that to the second shot, we see a blurring at Z227. Working back 7 frames would indicate a shot fired at Z220, close to what you and Lattimer have hypothesized. If we apply that to when I think the first shot was fired, we see a bad blurring at Z158 which would equate to a shot at Z151.
We need to recognize the limitations of our time piece which is Zapruder's camera. When I say there would be a 7 frame lag between the firing of the shot and Zapruder's reaction, that is an approximation. Even if that figure is a constant for all three shots, there's no reason to assume that number is going to be an integer. In fact, most likely it is not. Maybe it is 6.74 frames or maybe it is 7.31 frames or any number near 7. We would need to conduct a test using a camera capable of thousands of frames per second to determine a more precise lag time between shot and reaction. The best we can do with what we have is calculate an approximation, accurate to with 1/18 of a second.