if he was actually on Main?
Where in my post are you interpreting anything at all about them being on Main? Read it again please. Couch said the same thing that Jackson said except Couch said they “had just made the turn.” Both said they were looking back at Featherston scrambling for the roll of film.
I thought your position was that the first shot occurred 1/3 second before this first frame of Hughes last clip on Houston:
Where do you think the 3rd camera car is at that point? Since it is not yet in the frame, it must be still on Main St. It might be starting its turn onto Houston, but the entire car is still on Main St.
Do you really believe that they were still looking back at Featherston scrambling for the roll of film when they were half way down the block? Do you really believe that they were still looking back at Featherston scrambling for the roll of film over 3-seconds later (when you believe the first shot occurred?
Jackson said it was "approximately" that time (when they "all looked back at him and were laughing") that they heard the first shot. He said that they were approximately half a block on Houston Street so I take it from that it was just a moment
after the dropped film incident. He is relating the last moment that he recalled before the first shot. If so, then it occurred a moment after the last frame in Hughes' film, which shows the 3rd camera car almost up to the end of the first building on Houston:
According to Dale Myers, that last Hughes frame was exposed at the same time as Zapruder z185. That fits with my analysis as well (a bit more than 2 seconds after z145). It is not just Hughes and Jackson saying that this was before the first shot. Betzner said it was after his z186 photo. The occupants of the VP car said that they had completed the turn (it is still turning at z181). Phil Willis said it was an instant before his z202 photo. Occupants of the VP security car and witnesses along Elm provide a similar time for the first shot. I would suggest that the convergence of all the evidence on a post z186 first shot is highly unlikely to be by random chance.