Since swapping to my most recent mouthpiece, I've found the altissimo 
quite a bit harder to get.

I was just wondering if it has more to do with the smaller tip 
opening, or the longer facing (or both?)... Does anyone have any 
ideas?

I've relatively roughly refaced a Rico Royal C5 to about 75 thou, and 
I'm going to do some chamber work on it, and then "fine tune" the 
facing. I don't really want to change the tip gap by much, but the 
facing length is a variable to a certain extent.

Should I "fine tune" it to 18-20mm, 20-22mm, or 22-23mm facing length 
in order to get the altissimo back?

Thanks in advance.

Danny