Ah yes. In Seinfeld parlance - The magic loogie!
That diagram is as much a lie as Specter's 'Magic Bullet'. Connally's seat was NINE INCHES LOWER than JFK's.
As to Connally's injuries, if you watch the Zapruder film, Connally turns to his left at the first shot, then turns to his right just before he is struck by the the third or fourth shot. The 'Grassy Knoll' was on his right -- no way can you tell me that he heard a reflection of a shot from that direction; there is nothing there to reflect any sound waves, indeed the shrubbery and trees would have deadened them. He heard a shot, and turned toward it.
The Warren Commission lied.