[12 piece bucket]

That's right, Smooth.

The Clubshaft will remain at all times in the plane of the Left Arm Flying Wedge. This plane is the vertical plane of the Left Wristcock Motion. Hinge Action -- the Flat Left Wrist held vertical (perpendicular) to one of the three Associated Planes (Horizontal, Angled or Vertical) -- will determine the amount of Clubhead Travel through Impact. Hence, it also determines the Clubshaft position during and at the end of the Follow-Through (the Both Arms Straight position).

As Tongzilla has indicated above, the Clubhead (and, likewise, the Clubshaft) travels furthest when the Left Wrist is held vertical to the Horizontal Plane (Horizontal Hinging). Both travel shortest when the Wrist is held vertical to the Vertical Plane. Finally, the Left Wrist held vertical to the Angled Plane of the Stroke produces a Clubhead/Clubshaft Travel somewhere between the two.

In TGM, Rhythm is defined as maintaining the In-Line relationship of the Clubshaft and the Left Arm. Through Impact, that condition is maintained by the Flat Left Wrist executing its Hinge Action. Therefore, the answer to your question is that the Clubshaft position is determined by the Rhythm of the Stroke (as determined by the Hinge Action employed).

Boss . . . There are some pics in the Gallery of Champions who maintain the forward lean AFTER impact. Would you say this is a result of a "specialty" shot? Or possibly Grip Type? Or they are just plain Champions and thus compress the ball better this way?

Also, inorder to achieve the position/alignment would the left arm flying wedge continue to be somewhat turned?