I've looked at the SP-101, but it seems like an in-between frame size. The 4 inch barrel is 29.5 ounces, so pretty much like the weight of a K-frame minus one round. Revolvers are already capacity disadvantaged, so subtracting a round isn't something I do lightly.
I know it can take full power magnums, but how comfortable is that going to be out of a 29.5 ounce revolver?
If you're going to shoot full power .357, then a GP-100 or a seven shot 686 P is only about 9 or 10 more ounces more. Either will hold up to extensive full power loads.
(Another good choice would be a Glock 20 auto. Hard to beat 15+1 rounds of 10mm auto for 27 ounces.)