[Daryl]

maybe taking this a bit off topic but does the rotated shoulder turn = easier to keep head centered?

That seems true for me but I don't focus so much on the Shoulder Turn. I try to move the Hands onto the TSP ASAP. That pretty much takes care of the Shoulder Turn.

I've noticed in your recent video that you've moved in that direction too. But how do you get the right amount of Flat in a Flat Backstroke Shoulder Turn?

I think the Stationary Head and EA allows the Hand Path and thus determines the Shoulder Path, not the other way around. It works well for me because when the Shoulders get Dragged by the Hands while your Head remains Stationary, your Shoulders have only one path to follow.