Look at 250 or 255 grain RNFP bullets, and also Lee's 230 grain truncated cones.
What you probably want are max loads from the "normal" .45 Colt charts (not the "Ruger" loads) using a medium-slow powder like Herco or Blue Dot.
ETA: Then there's always compressed loads of Black Powder. That works really will in .45LC, almost like the cartridge was designed for it