Your defense of their pointless study is that they didn't use Bennett?
Roselle and Scearce couldn't use Bennett in their fine study because, although we can see him looking sharply to his right in Z-135, z-136, 137, and (most clearly) in Z-138, and we can see him looking straight ahead by Z-142, and we can see him tilt his head to his right to see around Powers from about Z-144-on, we can't see him in Z-133 or Z-134 due to the sprocket hole, so we don't know if he started looking sharply to his right in response to hearing the first shot or if he was already looking in that direction before the first shot rang out. The important thing is that he started tilting his head to his right to see around Powers to see if JFK was okay around Z-147, i.e., about 1.25 seconds after Oswald's first, missing-everything, shot at "Z-124." The time interval of 1.25 seconds (or slightly shorter) suggests that Bennett was already looking sharply to his right while "scanning the crowd," and that his turning his head and starting to look straight ahead by Z-142 was his conscious (i.e., non-"startle") reaction to the sounds of the first shot.
Post a blow-up of the Z-frame you believe shows Bennett looking round Powers, because I don't see it.
Google "Costella Combined Edit" and go to Z-150 for a pretty clear one.
You're welcome, btw.
All three men [Landis, Ready and Hickey] state they turned to their right rear as a response to the first shot.
That's what their confused recollections told them to say, but when they say they turned around to the rear, they're obviously referring to what they did in response to the second shot, i.e., the one around Z-222.
Ready, however, gives us a clue that they were all wittingly or unwittingly referring to the second shot when he wrote (as you so kindly posted, above), "I heard what appeared to be firecrackers [plural] going off from my position. I immediately turned to my right rear [after the second "firecracker"] trying to locate the source but was not able to determine the exact location."
You do realize, don't you, that Altgens-6 equates to Z-255, 1.80 seconds after JFK and JBC were wounded by Oswald's second bullet, CE-399?
All three men are shown turned to their right rear in Altgens-6.
Correct.
The Z-film does not show this movement.
Correct, because by Z-200, i.e., 1.2 seconds before the second shot and 3 seconds before Altgens-6, the pertinent people (your Landis, Ready and Hickey) in the Secret Service follow-up car were no longer in the frame.
D'oh!