gdong

the 20G is hard, but I have seen it help with my air flow and relaxation. I'm into long G's and low F#'s right now, they really help me, but not for 20 minutes. The method itself is all about isometric strength building. If you are rock solid in your mouthpiece position and don't move at all between registers ever, then this mothod is worth a shot, it will really build strength, but you need the flexibility to use that strength. If you are still unstable in the mouthpiece position, get stable or you will just be frustrated with any high-note system.

Cat was sort of a natural high-note player and I feel that his method reflects what he did to improve and maintain his facility, not as a method to high notes. As for recommendations, i would find a method by someone who went through embouchure troubles/accidents and came out on top. They would know really how the mechanics work from the ground up. Someone like bobby shew or ken larson comes to mind there.

I would recommend Jim Thomsons buzzing basics for as long as you feel you need it (4 years for me!). It will build strength and flexability, then take it to the upper register with stamp and caruso.

Good Luck!