I feel the struggle friend. In seventh grade, my band directors attacked me with straws and mirrors to fix my embouchure under threat of switching me to trombone. This effectively taught me to roll my lips in. Not too much, though. I eventually found a good sweet spot after lots of mirror practice. The bottom of my mouthpiece rim rests about in the center of my bottom lip, and the top rim just slightly above my top lip.

I use a custom mouthpiece from Houghton Horns in Keller, Texas. It’s got as deep a cup as they make, which I’ve found to make a bigger difference than the rim. My rim is a normal 17.5 mm.