[O.B.Left]

OK stankbutts how's this then.

So I was looking at the Amazing Changes section. It looks like the line drawn is the turned shoulder plane.

So the question is this. Is the goal to get the hands clubshaft and the right shoulder to stay one this plane in the down stroke?

Assuming you are using the TSP, Axis Tilt etc, yes. The Right Shoulder accelerates and takes the intact fully loaded power package, bent right right arm down plane towards the ball with out any power spillage. Power is "accumulated", "stored" and "delivered" to the "release" point. For the right shoulder to accurately deliver the stored power it must travel down the inclined plane.

Then at impact should the clubshaft, hands, right forearm, and right shoulder be on this plane?

NO. The right shoulder can not be on the same plane as the right forearm assuming any right elbow bend. The right forearm flying wedge should lay on the Inclined Plane through impact. The right elbow should be bent at impact saving some thrust (passive , swinging or active, hitting) for the ball. The boxer punches, extends his arm through the target with a bent elbow at impact and full extension past impact. The golfer does the same, bent right arm at impact , full extension at Follow Through, Both Arms Straight. "Having lots of right arm" left for the ball is a key to compression.