I thought I wasn’t physically built right somehow and thats why I was limited to pretty much G above the staff, despite years of lessons, practice and dedication/effort. I gave up in my early 20s. A couple years ago in my late 40s I stumbled across Gregs and others’ YouTube videos. I had nothing to lose and for some reason I believed what Greg and others said–that I could play whatever I wanted on the horn. I cant hit double C, I’m not there yet and have only hit Double G occasionally, but I had never even touched a High C. A high B natural a few times, but not High C. Now, I am able to play above the staff comfortably and relaxed.
I thought perhaps because I had no overbite or under bite, my teeth meet in the middle, or I still have my wisdom teeth, my top lip is thin, etc., etc.
In hindsight, my limitations were in my brain. I still have limitations I’m working on, but I no longer doubt that I’m capable of playing above the staff. High C is not hard, nor D or E.
Ironically, we have to let go and relax for our lip tissue to vibrate as freely as possible to achieve the highest pitches.
The keys that helped me were:
1. Less air is required the higher we play
2. The notes/harmonics are closer together the higher we ascend (I.e. the open position harmonics above the staff are G, Bb, C, D, E, F#, G–a half step!)
3. We want the lips to interact with the air like the vocal chords.
I started playing softer, but with a consistent release of air and I focused more on being relaxed and having a resonant sound and I believed I could change pitch with very little movement, no tilting my head back, bell down, lip in / under, etc. I was willing to miss, had nothing to lose…but the note came out, then my first High C then notes above. I still have a long way to go, but my point is that I believe just about anyone can play anything. There are probably exceptions, but those must be a relative few extremes.
I recommend you take Greg up on observing you play. He cant tell you what to do simply, we have to experiment and figure it out in our mind, but I dont think there’s a better guide.