Basic and Acquired Motion and Plane Shifts
 

I'm sold now on practicing basic motion - I finally understand downward thrust to both arms straight (Huge AHA moment)! But I have a question on backstroke and downstroke planes for basic and acquired motions for a single shifter vs. a double shifter:

Double Shifter Basic Motion: backstroke and downstroke fully on elbow plane.

Double Shifter Acquired Motion: shift from elbow to turned shoulder plane in backstroke and back to elbow in downstroke?

Single Shifter Basic Motion: backstroke and downstroke fully on turned shoulder plane (there seems to be no time for a shift?)

Single Shifter Acquired Motion: shift from elbow to turned shoulder plane in backstroke and stays on turned shoulder plane for downstroke.

For example, I believe Yoda mentioned that he might use mid body hands for a swinging procedure basic motion. I wonder if this would involve a plane shift from elbow to turned shoulder plane in start up or if the shaft would start on the turned shoulder plane?