D why do you equate the Wild Bill Melbourne drill with a pendulum drill. Impact alingments are awesome for even the newest of golfers when they do this drill. You should see on film how the Steering disappears , the release is delayed etc. It's a way of tricking the Steering out via continous motion. Like being able to actually hit a ball with a practice swing.
I was referring to the MacDonald Drill as a Pendulum/Swivel Drill. Ben Hogan and others used it all the time and til this day. I think it's being used because the Right Forearm Angle of Approach is unknown. Still, it's useful and very helpful for many people.