Well it's pretty clear that this is on the level, I'd be happy to participate. I'll fill in the survey and hope others do too.
You know the old joke "doc, it hurts when I do this"... doc says "don't do that!". Well, that won't work for me.
I would like to ask a couple questions:
When I teach someone how to cast, I always advise to keep the elbow close to the body when learning. I use the metaphor of an ol' timer smoking a pipe and holding the Saturday paper under the armpit on the rod side to reach a rise. Not touching the side, but comfortably downward. Of course when extending the stroke for long distance casts, the arm extends along the loop vector to the rear; and of course when taming a tailing loop the arm carries forward to point the thumb to the target - but through the middle of the power stroke the elbow should not be out away from the body.
I've heard that an extended arm through the casting stroke contributes to shoulder soreness, and I've found (anecdotally speaking) this to be true.
Is there any basis in medical science for this?