The various arguments I've presented in this thread have led me to a first shot at z223. Assuming this came from the sniper's nest the shooter would have approximately one second to take aim and fire after the limo emerges from behind the oak tree (at z207). I don't really know about these things but it seems reasonable to me.
The problem with a first shot at z223, apart from the need for an instantaneous facial and hand reaction, is the relative timing of the shots.
As I have pointed out, the overwhelming timing evidence is that:
1. there were 3 shots.
2. the head shot was the last shot
3. the last two shots were in rapid succession, the second shot being perceptibly closer to the third than the first: 1...........2......3 (A shot, a pause and two shots in rapid succession - see for example SA Lawson, Sheriff Craig, Ladybird Johnson, Luke Mooney, Mary Woodward, Pearl Springer all set out in
my tabulationThe FBI determined that 2.3 seconds is about the fastest that two aimed shots could be made with Oswald's MC.
2.3 seconds or 42 frames prior to z313 is z271.
If the first shot was at z223, that would make the first interval 48 frames (271-223). That is a ratio of 48:42 which does not fit with the shot pattern. But a first shot around z190-200 (81:42 or 71:42) fits the pattern. That shot pattern fits pretty much the rest of the evidence as well - except Connally being hit in the back by z230. Perhaps he wasn't. Perhaps he was just turning around to see the President after realizing, in horror, that he had just heard a rifle shot and was fearing an assassination unfolding. After all, both he and Nelly said he turned around to see the President before he was hit in the back. By z271 there was a clear path from the SN to Connally's back that just passes to the right of JFK's head. Hickey said that JFK's hair flew up on the right side at the time of the second shot but it did not hit him. Where should we look for that hair flying up?