Happily transcribing Miles' solo off So What when I suddenly need to hit Altissimo G. I know its a difficult one but any suggestions otherwise I'm gonna have to drop an octave which will be a shame. I just cannot do it.
Keep at it, your tone will thank you. One thing that helped me a lot is practicing scales on the mouthpiece alone. You can play a 10th on just your mouthpiece. Play scales and scale paterns just using your vocal cavity to change the pitch (OK your chops move a little but you're not raising the pitch by biting, you're doing it by raising the back of your tongue).I'm finding overtones and therefore altissimo difficult. I have also just got a transcription of the Miles and Coltrane solos. The good news is I have all the right notes but in the case of Miles, I am an octave too high so looks like I won't be needing the high G after all - pity, it sound great up there (well up to F#)