This is kind of a small point but i said i'd say it here for completeness. You have the head shot occurring at 12:30. It should actually occur at about 12:30 and 30 seconds. This is because when the vice-presidential car turned the corner onto Houston street, Rufus Youngblood noticed that the Hertz sign ahead of him (on the roof of the TSBD) was already reading 12:30. Here is the relevant WC testimony:
Mr. SPECTER. Are you able to fix the precise time of the assassination?
Mr. YOUNGBLOOD. I would say 12:30. I was to keep the times. The Vice President was asking me if we were running on time, and so forth. And so he asked me how much further, and I would call back to our followup car and ask them how many more miles and so forth.
So, for this reason, I was at that time keeping up with the time very closely. And when we turned the corner, I noticed an illuminated clock sign on this building, which I now know is the School Book Depository Building.
And that clock indicated 12:30. And the reason it is significant is because this was the time we were supposed to arrive at the Trade Mart.