Quite a few people have success with Doug Elliott’s system that can support larger diameter rim sizes and shallower cups, just wondering if anyone has had any success with Greg Black’s larger rim C cup pieces on typical .500 and .508 small bore horns (5c, 4.5c, 4c etc.). I’ve seen the 5C referenced as designed for alto trombone, and from 6C and bigger they all seem to have the same throat (.234) and backbore specs.

I currently have a 6C and 7CL but find his 4.5 rim quite comfy so was considering a 4.5AL and 4.5C.

They are good mouthpieces - I've used similar GB mouthpieces on small bores and alto for many years. I am currently using some slightly different pieces, but wouldn't hesitate to recommend Greg's mouthpieces for this purpose.

Jim Scott