I've read this article before, but thought you might find it interesting:
Ruger Blackhawk 45 Auto Loads
http://www.handloads.com/articles/default.asp?id=41
I've not messed with any of it myself in my convertible Ruger. I do have a lot of .45 Super brass, which would be where I would start, but I'm not sure what the results would be like.
I've flirted around with using
almost 460 Rowland starting charges in my .45 Super setup (Gen4 G21 w/KKM 4 port comp) and it's worked great, brass is strong and looks good. I'm getting 200gr over 1300 fps, 230gr at near 1250 fps and 250gr XTP/hardcast at almost 1200 fps (KKM bbl w/threading is right at 5" long).