Wow - great info!
I can add:
Use the rieffenhausser style/two piece shells normally spurned by handloaders; they have a greater internal capacity than the AA style, and you need capacity with bulky BP.
I like a tightly fitting wad for preventing blowby and ensuring gas seal: I'm using a .750" cutter for 12 bores. I also like to dunk my felt wads in wax as a moisture barrier for the powder. Some wise spark (was it WWG?) suggested that the cushion wad column height needed to be at least half the diameter of the bore ie 3/ to 1/2" in a 12.
RG
