I'd look at Speer Gold Dot Short Barrel .357 magnum 125 grain.
Plenty o' pop but not going to be as loud or flashy, with less recoil, than other rounds. In that SP101, which is heavier than most guns it's size, it should handle that round splendidly. You do NOT need barn-burning maximum power .357 magnum ammo in that gun, or any gun, for defense. It simply produces too severe a recoil and muzzle blast/flash/noise to be any good in a fightin' snub gun IMHO.
One is MUCH better off using these mid-power .357 shells in there snubs. Leave the hot full power stuff for a revolver with at least a 4" bbl.