You have to look at all the evidence that bears on shot spacing, not just evidence specifically about shot spacing. You have to look at evidence relating to where the car was the shots sounded; what witnesses say what occurred in response to the shots - particularly the first shot as well as the perceived relative shot spacing. Then you must try to fit all the evidence of witnesses, photographs, film, physical evidence together to figure it out.
With respect to the evidence of witnesses as to shot spacing, you have to look at all their evidence too, not just what they said they recalled about the shot spacing. For instance, you cite Nellie Connally's evidence as to what she recalled about the spacing being 1..2.....3. But she also gave other evidence that conflicts with this. She said that she looked back at JFK after the first shot and never looked back after the second, which she said she saw hit JBC. The latter statement is inconsistent with her shot spacing recollection because she looks back until about z270. That puts the second shot after z270 and that is evidence of a 1.......2.....3 shot pattern.
I believe Nellie has her head turned enough in the Willis 05 slide to see Kennedy. She saw him raise up his hands so she must be looking towards him in the Z220s. We can't know for sure, but my reading of the film suggests she doesn't continuously keep her eyes on Kennedy until the Z270s.
Robert HarrisWhen we see her clearly again, she's looking (assuming her eyes are looking straight ahead) at her husband, then turns her head back in the Z250s. She may have looked back at Kennedy again (and not recalled it later) or she could be looking towards the Secret Service agents to get them to do something. If the latter, she probably would have seen an incidental glimpse of Kennedy anyway. She turns forward in the Z270s, then does a rapid head turn back in the Z280s.
These back-and-forth head turns by Nellie between approx. Z255 and Z293 seem to me to be consistent with her seeking help from the agents.
Though she told the Commission: "I never again looked in the back seat of the car after my husband was shot."
She also said:
"I just pulled him over into my arms because it would have
been impossible to get us really both down with me sitting
and me holding him. So that I looked out, I mean as he
was in my arms, I put my head down over his head so that
his head and my head were right together, and all I could see,
too, were the people flashing by. I didn't look back any more."
She's saying she didn't look back after she pulled her husband towards her (beginning in the Z290s). She sort of says the decision to not look back came when she pulled her husband towards her in this exchange:
Nellie: "... after the third shot she said, "They have killed
my husband. I have his brains in my hand," and she
repeated that several times, and that was all the
conversation.
Spector: From that point forward you say you had your eyes
to the front so you did not have a chance----
Nellie: Yes, because I had him, and I really didn't think
about looking back anyway ..."
Nellie told the HSCA:
"The only thing I could do was pull him down and by leaning
over him, I hoped if anything else happened, they wouldn't
hurt him anymore. I never looked back after John was hit.
I heard Mrs. Kennedy say, "they have shot my husband."
One can isolate "I never looked back after John was hit" but the context is when she pulled her husband towards her. She told Larry King in 2002: "And I'm not looking back now because I'm tending to John."