But I still need more drills, more exercises, I need to give these guys more incentive to make the change even though it will take time and energy. And I need to make sure I use TGM to do it in the simplist, most effiecient way.
How about this drill?
I think this comes from a famous instructor (Butch Harmon maybe).
Have the junior use his left wrist/hand to "hook" his bent right elbow at address. Make to and fro Basic Motions to help the junior see and feel the relationship of right forearm to the pivot through impact to follow through.