Tuba mouthpiece

Derived from the excellent customizer referenced, but I also edited the OpenSCAD file a bit to tweak things to my taste. Tried to duplicate a Bach 22, but this design lacks the thick ring around the rim; I find that makes it leak a bit of air around the sides of the mouth if you're not careful. Still, it plays really well - I was surprised, and I (and the student pictured both) like it better than the Bach apart from that!