Of course we need to correct Vince. His statement that Brennan saw 3 men on the fifth floor is incorrect. Brennan only saw two, likely because we know Williams did not arrive to join the others until just shortly before the shots.
I would also point out that the idea that Williams had agreed with anyone to view the motorcade from the 6th floor that morning is an uncorroborated claim by Williams. Neither Lovelady or Arce were asked to confirm an any statement or testimony.
From "You are the Jury" by David Belin......
"Mr. Belin. I believe that you testified that you thought you recognized two of the people that you saw looking out of the fifth floor of the School Book Depository Building ... outside of the building sometime after the assassination, is that correct?
The two people that you saw, are they any of these three people here?
Mr. Brennan. Yes. I believe it is the one on the end and this one here, I am not sure.
The employee that Brennan immediately identified was Harold Norman. But he seemed to hesitate about the other, although he said that he thought
that it was James Jarman Jr. I deliberately tried to trip up Brennan:
Mr. Belin. Could it have been neither one of these persons that you saw?
Mr. Brennan. I think it was one of them. I think it was this boy on the end.
Mr. Belin. You thought it was Mr. Norman. And what about Mr. Jarman?
Mr. Brennan. I believe it was him too. Am I right or wrong?
Mr. Ball. I don't know.
And at that time, neither Joe Ball nor I did know whether Brennan was right or wrong. The answer depended on the testimony of Harold Norman and James Jarman Jr."
I somehow doubt the truthfulness of Belin's last statement. Ball and Belin visited Dallas immediately before these testimonies. They spent considerable time with Williams, Norman and Jarman in reconstructing their movements in the TSBD.