Sennoc, your strokes are excellent - I peeked into the other videos also. You are one of the few people who is able to subject your body to the dictates of logic... normally, either the logic is missing, or the body is uncooperative! I agree with you, there is a beauty and symmetry about tennis that fascinates me, and to the extent that my middle-aged body will allow, my goal is also to make it as perfect a player as I can!
Upon reflection, I believe your statement regarding the elbow is correct, and its position and movement are a side effect of doing other things correctly. Great post, thanks!
Edit: Forgot to say, I look forward to reading your "Special Theory of Tennis"!