Been there and filmed it from a car moving same speed as well as from book depository. We teach long range shooting and the shot from the book depository is far more difficult than the grassy knoll. Also read the depositions from the Warren Commission by the doctors who took care of him. The primary questioner was Sen Arlen Spector. Every one of them describes a large occipital wound ( back of the head) with massive brain damage. Everyone of them was either faculty at Parkland hospital or surgical trainees who later became Professors at UT Southwest (Parkland), which was the premier trauma hospital in the US, or at Cornell. Not people who would miss that kind of detail. This would be more consistent with an exit wound in the back of the head.
I have been to both places. 68 yards at a target moving slightly downhill and to the left is a lot easier than a shot going left to right at 10 MPH in which you have to pan the target and hit it on the fly with a rifle. Easy with a shotgun which I do frequently during duck season.
And how did both shooters have the same lot number from the box of bullets found in the sniper’s perch?