I'm currently practicing the Haydn concerto for solo/ensemble coming up. I started practicing the piece using by Bb Xeno, and did not have so much fun. My teacher says, "oh, well lets just have you play an Eb since that's what is was written for and I think your ready etc.". (This is back in October) She gives me a Bach 304. The mouthpieces I have are a 16C4-GP(my primary that I only use), a 3C(I now absolutely hate in comparison), and a 3D (which I had for some reason I think out of experimenting). I figured at the time that a smaller horn made sense to be used with a smaller mouthpiece, so I tried the 3D. Much to my surprise it was terrible. It produced a better fitting tone, but the intonation was awful. I tried the 3C, and still disliked it. My 16C4 that goes in my Bb, surprisingly still seemed the best fit. Anyway, the leadpipe cracks as it's an old trumpet, and it gets sent back. After sitting in the shop for 2 months without a repair due to lack of parts, my teacher makes the gamble and hands me a much nicer E2D Shilke. I have never in my experience (then again only in 10th grade) played a more smooth, pretty... And expensive instrument. So I now play this, and decide I may try the mouthpiece switch out of curiosity to see how differently it behaves. Now, it plays so much better with a 3D. But like every other instrument I've played my 16C4 seems to play well on it too. So my conflict is, what would you say is a more appropriate mouthpiece? On either one, I can play great and get a good tone on them, just one being on the dark spectrum and the other more bright. I'm also curious what other people find with switching mouthpieces on different sized trumpets. My original theory of matching the mouthpiece and horn ratio was ruptured, so I would like to know the general consensus of that sort of thing. And I completely understand that mouthpiece choiceces are completely opinionated and that it's whatever feels best for me- but go ahead and entertain me anyway.