Left forearm orientation at Top and End

[streak]

(This question is really about needing a better understanding of left wristcock at the transition from back- to down- swing.)

Yoda noted in one of the Gallery videos that the left forearm is composed of two major bones: the radius intersects the left wrist joint near the thumb, the ulna near the heel pad. As the club is moving in the area of Top and End, the shaft is moving on a plane. Should the two forearm bones be aligned on or parallel to the shaft plane, or should they be rotated somewhat? Any comments appreciated about pros/cons of different orientations at Top/End and how such orientations may change other parts of the Full Motion.