Re: The beauty of the "Black Keys" for "Blue Notes"
Axshully, we're talking about John, not Geno, but I digress...
I don't see any possibility that these songs were played on a single row, or a triple row. We're talking Eb minor and F# major. What kind of crazy diatonic could be used to play in those keys? Certainly none of the commonly available ones, that's fer sher.
But on a piano accordion, it's real east to play in those keys. And John was known to play on a piano accordion now and then, but not as his main ax. It was more of a novelty or "me too" kind of thing.