On your legit piece, right? If you can play more than a 3 1/2 well on your jazz piece, you need a bigger chamber. Bird played a 5 on what would be a 7* or 8 in Meyer or Otto Link, but he was a freak of nature. The only downside to playing with a reed as thick as a 5, is that I can guarenee you that you can not play a pianissimo low D, and not have that hissing airy sound. For how much richer it makes your middle and upper register, it takes away from the lower portion. I play a 4 in legit. Any higher for me and low notes aren't as airtight.

Oh yeah, definetly switch to a hard rubber piece on alto. There is nothing more obnoxious than a metal m/p on an alto(with a few exceptions).

Yeah, a good jazz piece on alto for highschool's a Meyer or Otto Link. I personally prefer Otto Link, and I play a link, but students usually go more to the Meyer. If you've been playing a metal piece, then am I correct in saying that you can't push your C* enough in jazz? Also, with a hard rubber jazz mouth piece, you'll have way more control and be able to get more expression into your playing. As far as sizes...If you've been on a metal mouthpiece, you should have no problem playing Meyer 6 or an Otto Link 6* or 7. Basically, with Otto Link the * means half size in the chamber, so it would be either a 6.5 or 7. Also, both of these are under a hundred bucks, so they are quite affordable. It might take a few weeks to a month to get used to the new m/p, but once you do, your jazz tone should be better than ever.

Actually, it's not your fault you can't push that C*, it's that the chamber is too small. The chamber I would guess is comaparable to a 4* link, so yes, it will give out on you in jazz. Also, there is a different concept to pushing air through a jazz piece like a link, that your teacher can probably help you with. You have to focus on blowing the air through the piece into the end of the neck, lke it's going to keep going straight. That's how I look at it.