I haven’t been able to find any models that size that have articulating extremities, etc. (Gumby style). Here’s a photo using what I have to give a rough idea of what I believe the positions were fairly close to. As far as Andrew’s twisted pretzel position, I suggest you sit in a low-to-the-floor seat and try it yourself. If you can manage to place yourself in that position you will find it uncomfortable and not something anyone would place themselves in for a lengthy motorcade route.

I'd say the shoulder position of JBC is reasonably close to what it would have been when the single bullet struck. The problem with using those dolls is the shoulders can't turn independently of the hips. JBC's trunk would have rotated more than his hips which probably turned some but not as much as the shoulders. The legs would have turned even less. There's no way I could believe JBC would have rotate to his right while his left leg flare way out to the left. That's just one of the numerous problems with his goofy theory.
It's an easy proposition that anyone can test for themselves. Sit in a chair and try to look over your right shoulder. I think you will find that your legs will turn in the same general direction as the shoulders. They won't turn as much, but they will turn. It would be completely unnatural to rotate your shoulders while at the same time your left leg flared to the left. It just didn't happen.
Andrew has been stuck with this scenario for at least 18 years going back to when he was peddling it on McAdams' forum. It made no sense then and it still doesn't. He keeps trying to force as square peg in a round hole.