No original mouthpiece but leaning towards Morgan.
If you ask nicely @lostcircuits……he would probably make you guys one fine RPC. He plays a C SOP.good move. i have yet to find a c mpc for my buescher c sop. i cut the shank off a yamaha 4c or can use a runyon custom which also works on c sop
Actually testing with a Yamaha 6CM, which is a square throat like an S-80. I have to push it way past the cork to work in tune, in top of the octave key. Even with the pads completely worn out, I can get a seal and pop some notes. Against a tuner, I am getting notes in tune in C (I can only play G1 and above right now as anything lower won't play until overhauled).I have found that both a Selmer S-80 C* and a Rousseau 4R work dandy on both my Bb Buescher and my C Holton. .
Thanks, good to know on low Bb. I hope the Morgan won't need to be cut and will work as intended.You'll very likely have to cut a bit off the end of most MPs.
Beyond that, when you get it repadded, check low Bb. I found my Holton C was well in tune everywhere except low Bb was wicked sharp. I cut a ring of 1/4" belting leather and contact-cemented it inside the bell; problem solved, no effects on low B or above; but I did have to tweak my C soprano peg a bit (made from a clarinet/flute peg with diameter of the upper part increased to keep the C soprano from wobbling).