Hey Glenn,

Check Gagne et freres, link.
Their music store is located in Quebec city, not far from the Montmagny annual accordion festival location.
Old store, and they do "know" about accordions :).
E-mail or phone Richard Gagne, hell of a guy, an authority on Quebec accordions,their tuning and their past and present makers.
He should be able to give you the "definite answser" on accordion tuning in the Province of Quebec.
Other sources are of course Junior Martin, Larry Miller,and Marc Savoy, as they also sell some of their boxes to the Province of Quebec.
Check also the other link, I provided , a nice man, and builder Clement Breton, nice box too.

Salut.

Claude.