Three or more of anything in a session, but especially three or more melodeons.

Someone once said, "I never heard a tune palyed on ten melodeons that wouldn't have sounded better on one."

A single melodeon, plated well, or two played together, sensitively, can be great.

Hurdy gurdies can grate after the first twenty minutes.

Kendall: the Saxophone may often sound like a kazoo. For an example of it not sounding like a kazoo, listen to the late Paul Desmond (played with Dave Brubeck, and made an album with MJQ). It's not "Mudcat" music, but it's a beautiful smooth melodeous honeyed sound.