[Yoda]

I presume that when you state "stiff-wristed right forearm slap" that you are not implying an active release of power accumulator #1 (due to an isotonic contraction of the right triceps muscle), but rather a well-sequenced release of power accumulator #4, and then PA #2, synchronously combined with the optimum amount of isometric contraction of the right arm/forearm muscles that allows a golfer to sustain the lag.

Exactly right.

Moreover, I am referring to the Swinger's Feel -- monitored in the Right Forearm and Pressure Point #3 -- of sustaining (not creating) Lag Pressure 'Through the Ball'. This Lag Pressure is the indirect drive of the Clubhead (7-11), and its associated Accumulator #3 Action (Clubhead Overtaking) is the product of the passive Accumulator #1, i.e., the straightening Right Elbow per 7-3, 7-20, 6-B-3-0 and 10-11-0-3.

In my own case, my Right Forearm through Impact feels as if I am pressing the palm of my right hand on the inside of a doorway (with the Pivot and its Right Shoulder leading the action), but the doorway won't move. Presumably, this is the "optimum amount of isometric contraction" to which you refer.