A nice thread- could I indulge myself                              
I was travelling with my father as a boy- he was a schoolteacher, and taking a school trip to Swizerland. He bought me a Sonny boy, and I found I could play pop tunes like Wooden heart etc- I was about 12. Years later, having not touched a mouth organ for years I bought a second-hand hohner polkerwork one row melodeon, because I'd seen some morris dancers and found I could "instantly" play it. I have always kept the in-out breathing that goes with harmonica playing, and of course melodeons are simply big harmonicas. What I found over the years of buying and playing these instruments is that when you start using a different size box there is a transition time when I almost collapse from getting my breathing in a twist, especially playing music like the B minor parts of French tunes that are back to front. Have you harmonica players a similar problem ?