"Hogan "looked" flatter because he had SUPER FLEXIBLE wrists that gave him a whole lot of wrist cock with very very little arm swing."
His wrists may have been very flexible. But is was his Right shoulder flexibility that allowed him to get so flat. That is how he was able to get his right forearm vertical at the end of his backswing. Most people do not have that range of motion in their shoulders.
Again, you are being fooled. He is not flat, he just LOOKS that way because the swing is so short and there is so much wrist cock.
I can put my hands in the same position as Hogan but since my wrists are not noodles the club will look much more "on plane." If hogan didn't have so much wrist cock and just kept moving his hands up the plane, he'd look what everyone today considers "Normal."
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I'm not a TGM or PGA certified Pro, but I did stay at a Holiday Inn Express last night
Look at the pic of a Double Shift or Single Shift in TGM....if you have the book...
The hands go to the inside (i.e. under the Turned Shoulder Plane) until about halfway back....when they are done that route (you can only go inside so much....i.e. whe the right elbow has stopped folding, the right arm will want to lift the club to the TSP) they start going up towards the TSPlane.
Check VJ:
...
Can you see what it would look like if VJ stopped his backswing short of where he did? Now envision it stopped short, with enough wristcock to make the shaft parallel to the ground (without Double-Cocking, most people will never come close to being able to do that with a short backswing)....
Can you see how this creates the illusion of a "full" swing?