Does anyone have a source for the exact rim width of the Bach 6 1/2AL? All I can find is "medium wide, well rounded". I would agree, as I have played on one for decades but made a switch to a Denis Wick SM4U a couple of years back with very positive results. I know the cup diameter is slightly smaller (25.4mm vs 26mm on the DW) but can't find a definite number for the rim width. Playing my small shank horns with the 6 1/2 AL and my euphonium with the DW SM4U I feel enough of a difference to consider a DW SM4U with a small shank, but I'm concerned about it being too big for the instruments (1930 Conn 5-valve double bell, and King 3-valve "baritone") as discussed elsewhere in another thread. Thoughts? Anyone with calipers have a real rim width number out there?

Thanks.