Matthew Gilchrest said:
If you can find one, a Conn 1 might be interesting.
I just received my newly plated Conn 1, from Dan Oberloh, for use in Miraphone 184 5 CU. It really did open up the bottom. I don't know if anyone has a pantographic lathe but, if anyone does, and you can find someone willing to lend a Conn 1 out, you could have one made. My guess is that this would be about $150-$200 but, since I am not in the business, I really am only guessing.
A cheaper way might be to look at a web site like Josef Klier
http://www.jk-klier.de/ and look at his matrix of tuba mouthpieces and find on about the same dimension as a Conn 1 and order it. Remember, the "A" cups are deeper than the "B" cups and the "B" cups are deeper than the "C" cups and so on. The only dimensions I have for a Conn 1 is cup width= 32.7mm (1.287") and the bore is 9mm (.354"). A Klier T3-AA or T4-AA would be an approximation of the Conn 1 depth. Klier mouthpieces appear to be made by the same people making Miraphone mouthpieces so a glance at Miraphone mouthpieces might show similar sizes, like a TU41 or a TU25. Klier mouthpieces had a slightly larger shank than Miraphone mouthpieces, which have the same shank size as a Conn 1.
On the other hand, if you want to scoot up to Scappoose, you can try my Conn 1 but I ain't shippin' nowhere. Conn 1's are far too hard to find to risk shipping.
Always make a good sound; audiences will forget if you miss a note but making a good sound will get you the next job.