I've been loving on my 1973 MKVI alto for a couple of years now. I recently bought a 1938 Selmer BA as a backup. I notice it is lighter in weight and though my hands probably aren't as sensitive as a micrometer, the bell wall feels thinner. The BA turns out to feel and sound more resonant. They are both a great pleasure to play. In fact the BA with MKVI neck is the best combination of parts. Anyone else experience a preference for a thinner walled sax (if that is actually the cause of the increased resonance)? Thinking too much...