golfbulldog--I guess I don't understand the concepts involved, but I hope you find the pictures useful.
I am asking questions about the relative movement of the rotational versus upwards/downwards motion of the shoulders. One of the concepts within TGM is that the right shoulder moves down plane. I , like many others i presume, used to get my right shoulder going down to soon... trying to go down plane... incorrectly... in most pro's swings the vertical height movement of the right shoulder seems to come later ... nearer impact...( compare Hogan 5 and 6 below - there appears to be more early rotation rather than vertical height movement of the shoulders)
See Brian's diagram here (cropped by me)
It does seem to help to focus on the left shoulder like Brian advises. TGM describes right shoulder movement because that is the part of the body that has an anatomical and geometric aligment during the swing... but learning this alignment does seem to be easier with your mind in your left shoulder!