Interesting one this. I have a custom number 5 on my tenor which I have now outgrown since practicing like mad on returning to the horn after a 25 year break. I am very happy with my mouthpiece and after studying the wealth of info on this site I decided to get it opened up to a number 7 by Dawkes in the UK as thats where I Live. I talked to a very nice proffessor about my problem and was advised that I would be better putting my money towards a new mouthpiece. He informed me that as these mouthpieces are plastic, the nature of the material did not accurately cut but expands/deforms when being worked, leading to innacuracies and an unsatisfactory result. Im tossing this into the disscussion board as this seems to be at odds with the general experiences of other members. I would rather keep my mouthpiece, it has a nice groove that fits my one wonky tooth! and would appreciate any info that could be of help.
P.S. anyone got a plastic Quantum number 7 for sale?