I figured i'd have to reduce the powder charge by 5-10% when going from FFg to FFFg- simply because it is slightly more dense. I don't plan on loads any heavier than 1 1/8oz., simply because if I can't kill it with that, I don't need to be hunting.
Good patterns, and clean, fully burning charges are for what I'm striving. So far, I've reached that, and tweaking it.
It's a pity, but little
hard documentation and research has been done in the area of good hunting shotshell and muzzleloading shotgun loads with blackpowder. Simply put, it's a very small niche as shooting goes- as most blackpowder shooters are interested in rifle or pistol shooting- both of which are more straightforward with more easily quantifiable results.
It's a dad-burn full day's work to go to the range and set up and pattern shotgun loads. In all my years, I've only known two other fellers around me that actually went through the trouble to see how their shotguns patterned and where they shot.
Oh, here's the Goex load chart for shotshells:
http://www.goexpowder.com/images/Loa...-SG-Shells.pdf