[DrWho]

before the big boys chime in, I will say shoulder plane was always a bugger for me to understand, that said, I know your answer is in 10-13-C and 10-13-D. And our only concern is with the right shoulder staying on plane, the left only re-acts to the right. Understanding the shoulder plane always gave me a problem because my only 'on plane' concern was the tracing of my right forearm. I have since increased my spine angle and stack myself over my left knee more which has shed more light on my shoulders and plane angle than before.