I like Wolff springs; the standard power mainspring is still a touch lighter than factory, and to my hand linear in its tension wind-up -- no stack, perfectly even resistance throughout pull.

Per Wolff's strong recommendation, I don't use their reduced power versions as all my revolvers are defense tuned.

Suggest buying a couple of fresh strain screws and fitting them to any new mainspring so they become a pari, rather than using the factory original with new springs -- you'll save yourself some extra tuning this way.