Hi Terry,
As I say, different people have different ideas as to what tones best suit certain types of music, and I respect the fact that my opinions are just that.
To my ears most wooden bodied CBAs derived from French folk diatonics have a sound that I associate with folk music, but that's just my own observation. Maybe it's their appearance as much as anything, and I do realise that various folk styles worldwide play a major part in keeping the accordion alive with whatever tuning they use.
I suppose that Azzola wasn't a jazz player in the true sense of the word. Along with Astier, Baselli et al, he was a bit of an all rounder. As you mention their jazz work largely stuck to the melodies, but that was the way it was then (in France). I never used to like their material at first, and initially preferred the more raucous sounds of the old fashioned three voice musette. However, it sort of grew on me, and after I watched an interview with Bruno Lorenzoni, who described how swing tuning had been incorporated into French accordion, I too made the switch from three voice musette to swing and americain tuned accordions.
No need to blow the windows out if you just want to play tunes without dancers. Certain genres rely on strong musette, but Mr Lorenzoni reminded the interviewer that by the 80s most "modern" French players had no use for it.
These days I just play my Cavagnolo Vedette 5 and Maugein Mini Sonora, and it wouldn't matter what else they brought out, as I've never heard anything of late that would cause me to want to change. My Cavagnolo would probably benefit from a complete new set of reeds, as it has seen more clubs than ten generations of cavemen, and it appears the last owner smoked 80 a day, but I'd be worried that new reeds wouldn't sound like the originals. My old horn teacher used to regularly blow cigarette smoke through his instrument, as he believed it gave it the type of sound he wanted.
The trick would therefore seem to be to buy a brand new Cavagnolo for about £10,000, then blow about £10,000 of nicotine through it so that any rough edges to the reeds are mellowed. Consistent with the unpopularity of French boxes in the UK, I bought mine for £1000, so I've saved about £19,000 and have the sound I like!