Though Blake used skipping stones as an analogy to his reflex swing, the analogy is not complete. In skipping stones the throwing arm is not being dragged through by the legs. That arm is quite active in the throw, at least in the way I skip stones. The throwing arm action is similar, IMO, to the action of a racketball forearm. I can remember as a kid when skipping stones, we would compete to see who could get the most skips. If you tried too hard, ie, whipped your arm through too fast there would sometimes be an immediate pain in the throwing arm.
I wrote in a separate thread of starting with my trail elbow further across the body at address. In the backswing I try to keep the elbows as close together as possible. It really does seem to help get the trail elbow further forward in an actual swing.
Peter, could you append a description of your 4.5 drill to this thread? Thanks, Jim