I use 5 different mouthpieces on 7 different horns with a completely different rim on each mouthpiece (this does include a trombone). Every rim is completely different, and all of the trumpet mouthpieces are actually different brands. I would love to have a second C and a third Bb. I just think that when possible, you should play with the equipment that works best for the given situation. A big factor in this is how many different playing situations you expect to find yourself in, and how different your sound concepts are in those situations. Another big factor is how you practice all of the different equipment. I have a bizarre pic mouthpiece, and while I have no problem switching seamlessly from my normal mouthpiece to the pic mouthpiece if I am regularly playing on it, if I neglect the pic for more than a few days, it can sometimes be a few days before I really feel comfortable on it again. Because of this, I make sure that I practice on all of my equipment regularly.
Jason Pellett
www.atlantabrassalliance.com/trumpetlessons.html