Before anyone *believes* anything a witness has to say, it is essential to establish their credentials. In order to do that, some objective documentation is necessary to show, at the least, that they *could* have been where they said they were and experienced what they said they did.
Rather than a dip and dive, why not produce just one single piece of evidence that demonstrates that Whitaker ever saw the limo?
I produced the Ferguson memo which demonstrates he was with the limo after the assassination. I produced pieces of the bloody backseat leather which were removed from the limo four days after the assassination while it was still in the WHG. The WHG logs demonstrate that the limo was in the WHG on 11.26.63, as that was when Arlington Glass replaced the windshield.
Without credentials, Mr. Whitaker is blowin’ in the wind, Chris. I hate to be the bearer of bad tidings, but why not quit trying to kill the messenger? :-0