[EdZ]

The Down Plane Drive to Full Extension does not refer to the straightening of the Left Arm -- that Arm is already straight -- but to the Full Extension of the Right Arm. And that is why Thrust should be directed through the Aiming Point (and not just to it (10-20-A/B).

Yes, and if that right arm (and right wrist) still has room to straighten - which it does - then the force generated can and does continue to move 'away from center' until both arms are straight - the maximum distance that the hands, and thus the lever assembly, can move until the nature of a circle forces them 'up' - around the circle.

Both arms straight is the key - driving, thrusting, or using CF to get there, you must get there. I fail to see why Homer chose to select the left shoulder as 'center'. That view is arbitrary IMO, whereas looking at the overall motion, the center of mass, the center of the 'circular force', the center of balance is IMO clearly the mid point between the shoulders in all good swings. The true 'radius' is a line from the center to PP#1 in 3 dimensional space. Force vectors, not body parts. A line perpendicular to the shoulder line, at both arms straight.

I appreciate you view this differently, and see that you apply your view 'very' well in your swing - a more stable left shoulder, weight left move which IMO limits only power (mass) potential - everything else being equal. The advantage clearly being consistency over a slight loss of power potential.