I've also been taking special notice of other things from reports and keeping track. For example, so far in my work I've noticed:
1) Among police officers that were in the basement garage specifically to help with security etc, 22 of them were re-assigned elsewhere just before the transfer/shooting took place. Most were literally sent away from the garage between 10:45 -11:15 and sent to work traffic on a corner somewhere. Oddly enough about half of those officers were radioed and pulled from their traffic duty to go to Parkland hospital to help with security there - incidentally, this was after Oswald was already dying!
2) Among the officers or press that were in the basement and close enough to witness the shooting (and I'm not counting ones guarding the ramp or inside the jail office), 17 of them either didn't see it happen or saw but did not see the shooters face. They had to be told who the shooter was later. Some specifically even said that, as if they smelled something fishy going on.
As we know, Watkins reported that the shooter's face was covered. I don't yet have a definitive number of people that say they actually saw the shooter's face at the time of the shooting, however the number is relatively small. Some of that small number claimed to have seen the shooter during the scuffle, but we know that would be false since shooter's head was covered up.
Also, regardless of which group, most of the people that did see JR only saw him after the shooter had already been brought into the jail office - when he was being led to the elevator (kind of like we saw in Davidson's film). Regarding what the press saw, it's very tricky. Most didn't sign their statements and they were written for them. Only Jimmie Turner's and Pelou's (Frenchman) state they saw the shooter, someone that they found out was Jack Ruby (they didn't know him previously). Seth Kantor knew Ruby beforehand, saw the shooting, but he did not recognize him.
3) Immediately following the shooting there at least five different officers were told to guard the jail office door (from the outside) and specifically told not to let anyone enter. Not the hallway, but the actual office/booking room where they made the switch from shooter to Ruby. It appears that they didn't want anyone even coming close to where the switch was being made. Again, I think this is why everyone was told to leave the jail office and booking room just prior to the shooting.