[nevermind]

Homer:
"After a 13-B or 12-C Backstroke Shoulder Turn, the Right Shoulder moves toward Impact precisely on the preselected Downstroke Clubshaft Plane, establishing and supporting the Power Package Delivery alignments."

Nevermind
If the downsing has plane shifts, which plane angle is the preselected Downstroke Clubshaft Plane?
Given that the shoulder is on the Turned Shoulder Plane at the end of the backstroke, no matter which shoulder turn is used, how can the rear shoulder move downplane at startdown, on anything but that plane?

Tongzilla
Your preselected plane will be your Basic Plane Angle (10-6). So if you are shifting from the Turned Shoulder Plane to the Elbow Plane on the downstroke your hands and clubshaft should move towards that plane angle. Your Right Shoulder would never move onto the Elbow Plane because it's too shallow.
The rear shoulder can move on, above or below the established Turned Shuolder Plane (angle from ball to right shoulder at the top only, not during downstroke) during startdown.

Nevermind
In that example, shifting in the Downstroke from the Turned Shoulder Plane to the Elbow Plane, which is the preselected Downstroke Clubshaft Plane (Basic Plane Angle)?

Tongzilla
Elbow Plane

Tong thanks for your patience.

So, taking what I’ve learnt and implanting our example into the Homer quote I get this.

After a 13-B or 12-C Backstroke Shoulder Turn, the Right Shoulder moves toward Impact precisely on the Elbow Plane, establishing and supporting the Power Package Delivery alignments.

Either it's impossible for the Elbow Plane to be the preselected Downstroke Clubshaft Plane with either of those Shoulder Turns, or I'm still lost in the fog. You’ve already said that the right shoulder would never move onto the Elbow Plane, so I know it could never move precisely on that plane.

I can't see how any type of shoulder turn would allow the right shoulder to move toward impact precisely on any plane but the Turned Shoulder Plane (at Startdown and assuming that the plane angle has its Base Line on the Square Plane Line), but if you tell me that I need to understand 13-B and 12-C (I don't) to understand this quote, then I'll give it a rest until I've had another good read of my book.