I bought the pink ClayBuster 12 gauge 3/4 oz wads,. and followed the recipe of 16.6 Red Dot, their wad, Gun Club hulls, Nobel Sport 209 primers (in lieu of Rem or Win), and 3/4oz of reclaimed shot
I can't recall where I found it, but my 'standard' 3/4oz recipe uses 17.5gr of Red Dot under the CB WAA12L clone in the same hull but with a Fiocchi primer. My Beretta 390 cycles them flawlessly. Now that GC offers a 3/4oz wad, I'm gonna have to try it.
I have found that velocities run lower in reloaded GC hulls than STS hulls, presumably because the STS hull crimp offers more initial resistance than the GC hull.
Oh, and FWIW - CB shows a 17gr RedDot load for the new CB0175S in a STS/GC hull. It's rated at 1300fps (which, from your experience will likely be wildly optimistic) but at least you know that you can increase your charge to 17gr without fear of anything untoward happening...