As I said, there is not enough information to do anything other than speculate.
The panel in front of JBC has a metal panel and ashtray just above where JBC's knee may have been:

so it may have struck that and bounced back onto his clothing without doing any visible damage.
The thigh bullet was definitely CE399.
Well I’m still not convinced yet but maybe you will produce a drawing that has your proposed position of JCs body at Z270 and shows how he is holding his right hand holding the hat so that it aligns with the bullet path thru JCs back and front wounds.
If you can do that then I could live with the shooter having shot thru some tree foliage at Z193 because he might have been using the scope if it were aligned and zeroed , thus have his LOS very narrowly focused around JFK and his peripheral vision limited such the tree foliage “snuck up” on him just as he fired the 1st shot.
The misalignment of the scope could have been purposefully done by Oswald striking the scope against a column after the shooting, maybe to introduce some doubt should the rifle be found.
Then it might be possible that fragments that Nurse Bell saw which she thought came from JC’s thigh could be from Z193 bullet while flakes of metal seen in the X-ray of JC’s wrist came from another bullet. This would be contrary to the WC conclusion however.