[golfguru]

He has to become physically aware that he is shifting all over the shop. The old one leg drill will show him quickly (stand on left leg with the right pulled back) that little motion can be made to get a better and more consistent strike.

Often these shape shifters have a terrible notion of a consistent ball position. Even pointing that out can reduce where and tear on their body motions.

Fitting a "gumby" is harder than a good player. Correct length and a clubhead/shaft that they can feel is the first stop.