I think that, generally, the more powerful the charge of -2400 is, the cleaner it will burn.
I started with a hard cast 250 grain SWC, W-W cases, CCI large pistol primers. I started from 17.0 grains and worked my charge up to 22.0 grains, Elmer Keith's load. Very few kernals of detrius left behind. I went back down to Skelton's load of 21.0 grains, then down to BUFF's load, 20.0 grains. Through my 8-3/8 inch Model 29, I got about 1,350 fps, and through my 10 inch Contender, a bit over 1,400 fps. I regret not clocking the 21 and 22 grain loads.
I used a very stiff roll crimp, seating the bullets and crimping them in separate steps. My RCBS carbide sizer squeezed the brass tight enough that one coulld see where the bottom of the bullet was. It was as clean a load as I have ever obtained with cast bullets in the .44 Magnum.