Hi, Pat. It sounds like there are some similarities between us, but for me it’s higher notes where I experience the most problems keeping jaw down and teeth apart. I’m having no success getting away from decades of too high tongue arch and that arch always combined with closing up space between teeth. Add to that the embouchure change and I can’t figure out which way to go. Lower the jaw, quit with the tongue arch, change the embouchure and maybe change my style of tonguing all at once? That’s actually four things, each one affecting the other three. Yeah, I’ve clearly been working too hard at trumpet playing for a very long time. This is definitely confusing.