Bryan -
You really need to get a shotshell reloading manual. I recommend the Lyman Handbook.
Shotshell reloading is way different than metallic cartridge reloading. You do not "work up" shotshell loads, but rather you follow the recipes in the manuals exactly. They specify the hull, wad, primer and powder combinations, and it is recommended that you stick to those.
It is an interesting and satisfying process, and I think you will enjoy it. Have fun!
