Hi Alden - You don't say where in NH you're from, but if you want to go beyond reading, you need to plan a visit to our weekly music sessions at the Press Room in Portsmouth. There's nearly always two concertina players, and if you are in luck you can get to see, hear, try, both English and Anglo, to include Wheatstone, Lachenal, Jeffries, Dipper, and Morse, trebles, tenor-treble, and baritone.
I've PMd you my email and more details - Tom