I would try Universal Clays, AA#5, HS-6, WW231 or AA#2.
No matter what you pick, the 2 1/2" barrel will still belch fire and have a bark if you load to.357 pressures. Check your reloading manuals and pick a powder that makes magnum level with 5 to7 grains of powder, and you can use that same powder for reduced loads in the .38 to .38+P levels for plinking, and you'll find you shoot that snubby alot more with a lighter load, and keep those 158gr magnums for special occasions.