Interesting. I have been planning to post for a while as I am observing changes. Pre Windworks I had been using book two and slurring up to Eb above the stave but not able to use it in performance. I worked through this course fairly quickly and and was waiting for the ultimate level. While waiting I went back to the first video again and worked through with some improvements. I thought I had mastered the stomach tension but discovered that I had far more throat issues than I had realised. This lead to a rethink re the stomach as the two must be related. Back to the beginning again but this time with a different level of concentration, eyes closed etc..

I find that the real secret is getting the low C with total freedom. This gives a different chop position. I have developed a routine working through the singing C from the first C# exercise to the point where I felt some tension. Today was different again as I just focused the Eb singing C and the exercises without treating the exercises as a trivial extra but as a means of studying how well the process is working. Oh how different this felt. Just playing the Eb was a new experience.
I have been feeling the benefit of the course in my ensemble playing. In fact Saturday last was one of my best playing days for some time as it was all more relaxed. Playing loudly exhausts my chops rapidly but getting good resonance mitigates having to blow loud.

I can reinforce your direction about going back to the early videos. Each time I go back over them I pick up something I missed previously. I have been shown much of what you do elsewhere but nobody has put it in such a clear and constructive way. Playing endless exercises has no long term value without constructive self analysis and more importantly, without self criticism. Accepting where we are now is the best way to get moving to a better place. Starting from the right place is critical.