My vote for this is IMR 4198. I didn't get the accuracy I wanted with Varget in my .45-70 Handi, Re 7 wasn't much better and was dirty. 3031 was very consistent, but I ended up with a lot of unburned powder and those big honkin' 3031 grains in the chamber (and dents in the cases). 4198 took care of that, was just as accurate and consistent in my Handi, both with Rem 405 JSP and 405 RNFP hard cast lead.
I still use 3031 in the Marlin with 300 gr Speers (had bad results on deer with the Rem 300 HP), the pressure must be just high enough that I get a more complete burn with those at 1780 fos.
Good luck, and don't overlook the old stick powders!
Rick