I use a Rousseau jazz mouthpiece with a fairly wide opening. I get a big beautiful sound, and I can use it in both jazz and R&B situations. BUT the effort I exert to stay in shape (intonation, sound quality) seems too much. I'm wondering what a more closed mouthpiece would do? I don't mind using more than one mouthpiece (one for jazz and another for R&B), but I really want a set-up for jazz that is less physically demanding and also allows me to move around my musical world with a bit more ease. Any recommendations?