I'm on the comeback trail for the Nth time and for the Nth time trying to develop the high register I never had.

Going by what I've read here, I've been buzzing religiously in the evenings after an hour of the Eastman warm-ups each day. The smallish aperture on my SYM-T, I suspect, along with moving the mouthpiece lower on my kisser, has enabled me to reliably shatter glass buzzing arpeggios <span class="emoji" title=":wink:">😉</span>

Putting the M'pc in the horn I can't duplicate the success from buzzing. At least not yet. Advice?

Not without seeing what you're doing.