Here is where I stand. I recently had a lesson with my instructor who I trust and who has plenty of teaching and trumpet expirience. During this lesson I was not able to hit the assigned B flat above the staff (we try to add a 1/2 step every week). After playing something else that my range struggled with a bit he said he noticed I play 2/3 top lip 1/3 bottom lip. He said he never noticed it before and that it was more of a french horn embouchure. After watching me play some more he had me try buzzing moving the mouthpiece slightly. I got it to buzz just fine with a bit more difficulty and possibly some slight range limitations than what I had before. He said by going from 2/3 top and 1/3 bottom to 1/3 top and 2/3 bottom more pressure would be put on my bottom lip as opposed to my top lip and should help with range/endurance. He seemed very indecisive and said he wasn't sure if he wanted me to be moving things around since I had such a clear tone. We have been working on range/endurance issues for a while and he definitely didn't jump into the decision to make this change. (I'm suprised he actually suggested the change.) However he seemed to lean more on the side of doing it by the end of the session.
He said he wanted me to try to start moving the mouthpiece a little higher slowly over time. He said when I go on my vacation for about a week and 1/2 it would be a good time to work on this with just the mouthpiece buzzing. My next lesson with him is in 3 weeks because of vacation and marching band.
What do you think? I know I have to commit to it if I'm going to do it and trust it to work. I'm just a little worried now because of my teachers indecisiveness and the fact that I've read plenty on this website about how messing with the embouchure and moving things could have a dramatically bad effect on playing. Also because plenty of pros play the same way I do now.
The range and endurance is definitely a huge problem though and doesn't seem to be getting much better atm. I'd like to hear what your thoughts are.