Since I'm asking a question, might as well ask another one, what is a double shifter?
ckeller answered your other question. This one is easier:
Double shift = on the backswing, making a shift UP from the elbow plane to the shoulder plane, and then on the downswing, making a shift back DOWN to the elbow plane. A single shift would be shifting up to the shoulder plane on the backswing and then hitting from there all the way through. This is somewhat old language, as I get the sense that instructors who study trackman now like to talk about an infinite number of planes. You can take it back on all sorts of planes and hit it on all sorts of planes. But I think what I gave you is the standard definition of "double shift."
I think it would be easier for me to just see what you are talking about.
Any posterchild for double shifter and just shoulder plane hitter?
Regarding the first question....who said it and in what context? We all know these cliches get lost in translation
Brian always bring this up "he's trying to make room"
In the backswing? I thought he was talking about in the downswing.
Not new info. In NHA Brian talks about how a Sharp or early hip turn is great for most golfer, but it isn't for someone who needs the NHA pattern. The slide vs the sharper turn keeps the golfer from getting the hands too deep on the backing. The slide helps the up the wall, down the wall.
I am with you for the most part. Where I disconnect is when I hear one person talk about NHA for underplane, then another says sharper hip turn and stay closed in the transition to fix underplane. Those seem to be competing ideas.