Seems to me it is the right hand moving from under/in back of the left to
over/in front of it that moves the clubface from open (parallel clubshaft
downswing) to shut (parallel clubshaft follow through).
You are correct, azgolfer. The #3 Accumulator Roll (6-B-3-0) -- the
Open-to-Close Action of the Clubface (and, indeed, the entire Left Arm Flying
Wedge) -- is, in fact, actuated by the Right Arm.
[Don't be buffaloed by the terminology here; we're talking about simply 'closing
a door' by pushing on it with our right arm.]
However, for a number of reasons, Right Hand Control of the Clubface Alignment (in addition to its natural control of the Clubhead Power) is less than ideal. Therefore, though the Drive Out of
the Right Arm -- Active (Hitting) or Passive (Swinging) -- is
the Actuator of the #3 Roll, it is the Flat Left Wrist and its Hinge Action
(2-G and 7-10) that gives Clubface Control its fine tuning. It's what
Homer Kelley called...