Re: sharp upper register
Depending on how adventurous you are, you can also shim the palm key corks so they don't open as much. Best to wait until you've settled into your mouthpiece of choice before doing this if you want to go through this only once.
There is some risk that keeping the key too closed could make it stuffy, but I've found that this is the best way to lock in the high end without having to extensively retrain your muscle memory.
Once you've got confidence that high B, C, and C# are in tune, then go to high D and adjust how much it opens such that the same embouchre from high C# gets you an in tune high D. Then go to D# once D is is fixed, then adjust E, then F, then F#.
I am all for making sure you're not too tight in the throat at the high end which can cause this problem, but if you feel like you're straining yourself or having to use radically different embouchres to achieve good intonation, then I recommed shimming the corks.
Obviously, you have to either do this yourself or find a REALLY good tech who will do this with you at their side so they can custom fit the horn to your playing style.
I will be going through this procedure tonight with a new horn of my own, so this posting caught my eye...