I am sorry about your Dystonia. They should write in method books “keep playing this way and you will probably develop Dystonia, resulting in the symptoms of grief at losing your ability to play”.
What I like about Greg’s method is that the Science is correct. The physics is right and Greg has researched that credibly with UNSW and others. The physiology aligns with physics of “Body’s Concert Hall” and sympathetic oscillation and clearly defining the aperture and tightening the corners with lateral movement rather than vertical. The maths doesn’t change. Bringing in the concept of neuroscience is the first time I have seen it specifically used for this skill. Neural Pathway development and neuralplasticity is in any method (just not mentioned or understood) which is why 1.0 is hard to change for experienced players, but because of neural plasticity we can change to 2.0. I like the way Greg has overtly referenced it and emphasises not to rush because new neural pathways take time to develop. Greg brings in the psychology of playing reinforcing that anyone can play all over the instrument but also being able to close your eyes and feel (I find it useful to be able to isolate a feeling good or bad and name it). While we eventually want those feelings embedded in the sub-conscious, identifying them in the conscious mind while learning (process stage) will theoretically speed the development of the neural pathways.
I have no doubts about Greg’s methodology, it all stacks up. I have a problem with the field of Psychology. When we put music and psychology together, the concept very quickly turn into a Therapy, a modality of treatment, rather than a mechanism to assist the musician. Something akin to Sports Psychology, but for musicians.
Maybe a good Research project….maybe I could do a collaboration with my daughter (she is a research neuroscientist and part time brass player).