Some time ago I did a set of alternate drawings on the premise that the Dunkerque's were replies to bigger German PB/BC (like Syzmos Seydlitz) and the follow up Gascogne type would be bigger again. Seeing David Latuchs drawings of Alsace reminded me of these. You will note that I have carried the 5.1" quads through both drawings as I give the French the 5.1" as a good system rather than the problem it was.
The enlarged Dunkerque goes to 8x15" and 24x5.1".
The Gascogne goes to 12x15" and 24x5.1"