Everyone has a different mouth. That video link posted above is very true in my opinion. If it works why change it. A trumpet teach knows whays best. I play with a lot of bottom lip in the mouthpiece. I have been progressing normally for years. I also got braces and used the practically the same embrochue. My embrochue seems to fit perfectly. I have also noticed slight shifts in my embrochue naturally. Your body will most likely find whats best according to my band director.