Re: Jazz Mouthpiece
I was in your shoes about a year ago. I've got the Jumbo Java A55 for a really edgy sound, though it's got plenty of body to it - it's not anorexic 'ala Sanborn. I play a Selmer III, and what I've found as a nice middle ground is the Selmer Paris Metal Jazz mouthpiece. I play the C*, which projects more and plays louder than it's S80 C* cousin - so not all C*'s are created equal. I'm not crazy about the C* facing on the S80, but it works well on the metal jazz piece. I've played the Selmer USA jazz piece, too, but I like the Paris ones better with the rounded baffle as opposed to the straight.
The JJ (paint peeler) is hard rubber and the Selmer (a more refined edge) is silver plated brass, so I feel that mouthipece design has WAY more to do with the sound than what it is made of.
A dirty little secret is that the Jazz C* works great for legit, too, when using a bell mute. They are very responsive and articulate very cleanly. The responsiveness may be attributed, somewhat to the metal, but I couldn't authoritatively say so.
I have a vintage Selmer D (short) metal mpc, and it plays quite brightly and loudly. It doesn't have "Jazz" inscribed on the table like the C* does, but it sure plays like a jazz mpc. I'm not a historian, so I can't tell you too much more about the piece - only what it looks and plays like.
So I vote for design over material.
Check out www.mouthpieceheaven.com "Resources" for great info.