I've been trying for about a year to find a mouthpiece with a larger tip opening than my old(ish) 1990 Babbit Meyer 5SS. Both I tried created the weird dipping sound when pushed hard at middle e through g on my 1917 Buescher. The two I tried- A Meyer Custom opened by a reputable refacer to .080 and a stock Runyon Model 22 at about .077. I just got a custom New York jazz Drake Mouthpiece(.080) and it loves my old Buescher whereas the other ones didn't. Perhaps the length of the facing agrees with ME more and has nothing to do with the horn? any insight?