[wally888]

Drawing upon my very limited knowledge of TGM, I suggest the following: (consider all as questions!)
1. No mater how you place your right (bottom) hand on the handle, you will have a #3 PP. May not be the preferred place but will have one.
2. Concentrating on PP #1, getting extension on the backstroke and using a right forearm take-a -way will help you stay on plane.
3. Concentrating on PP #1 through impact will help you achieve a flat left wrist at and beyond impact. Also a bent right wrist.
Too much concentration on PP #3 can/will cause throwaway.
Of course all goes out the window if the right wrist cocks!
W/O knowing what I was doing, in the past, I often practiced with the right thumb and forefinger removed from the handle. Stopped throwaway for me. Also played that way on numerous occasions-if only I could have taken less than 34 putts!