By and large, I find a 3C mouthpiece (specifically, Denis Wick 3C) gives me best endurance for general practice. But I get a significantly better tone on bigger mouthpieces and often play either a DW 2W or DW 1CW on the basis that they're giving a better workout for my embouchure. Is this false reasoning? As a heads up, the follow-up question will be whether an 'advanced' trumpet is a better learning tool than a 'standard' production pro model. In my day gig, I often find myself being 'thrown in the deep end', and invariably this has been to the benefit of my capabilities as an engineer. Does the same hold true in the musical sphere?