Fit is king over everything else.
If your buying commercial cast, they are probly sized .357 or .358 and probly too hard.
You'll more than likely need .359-.360. I think 95% of the people that hate cast bullets have never made their own. With undersized, too hard of lube and too hard of a bullet, you will get leading. There is getting to be a few guys selling cast bullets that are sizing right and customizing the alloy, though I cant remember the names.
I rarely and I mean RARELY shoot anything but cast in all of my guns, rifles or pistols, and never have to clean any lead from the barrels.