I have a chart of CCI primer energies.
SP 500 = 5.5 ft/lbs
SPM 550 = 8.8
SR 400 = 6.0
SRM 450 = 7.2
I've used SRP's in .38 Super before and wouldn't hesitate to use them in .357 if I needed to.
For light loads I will always go with standard SP's, preferably Federal.