Date: 2016-12-30 23:48
You are much more accomplished than myself. I'm sure you'll figure it out.
Think about blowing into the hole for low notes and across for high notes.
Although I was not one of the best saxophonists or clarinetists in college, I was almost certainly the best flute doubler. I had taken lessons and practiced a lot. It's different enough that you feel very uncomfortable at first, but just work on getting a good strong tone. If you just started you should be getting dizzy. I don't know about underbites, but my HS flute teacher's upper lip was definitely pointed in the center, and to compensate she played to the side. She was once singled out in college as "someone who should not play the flute", due to the shape of her lip. Lips are flexible.
Make sure you are holding the horn still (which may be harder because of the LH index finger position and thumb levers - and/or your bite), and that you are comfortable leaving the first finger up for D, and are holding the Eb key down all the time. Sorry if all that is painfully obvious.
Take the flute to a good repairman. I struggled for years and years with my low notes, only to realize decades later in repair school that my foot tenon was obviously leaking like a canyon.
- Matthew Simington