Ok, so I had a teacher for a few months & we did a full mouthpiece placement swap (started with almost all bottom lip, switched to more top than bottom.) & for a while everything was going great - much better tone, more consistent, etc. only problem was my range went down a lot, but that's expected when making such a drastic change. But since he disappeared, my consistency has gone straight down the drain. One day i'll be playing with my usual range & usual tone, the next i'll play with the same range but as I hit a C in the staff, my tone gets really fuzzy. I've followed the same warmup & everything I did with the teacher, but it's not the same. Any ways to improve consistency?