Eric, I like Clay's set up, but I have some theoretical issues, though I don't know if they are significant enough to dramatically affect the end result negatively. It would be hard to argue that he doesn't make awesome bows, it doesn't seem to radically change the final result.
The balance point on the tree is directly underneath the centre of the handle , and inline with the rope pull. The pulling point on the string is the centre, which corresponds to a 3under draw, which Clay uses. However, when he cuts his shaped handle at the end of tillering, I would think that this takes the balance point off centre and pushes it up higher, where the thumb rests.