I fly fish in the summer and in late spring sometimes. Nymphing is a pretty good technique for those slower holes and deep slots. It seems this is a better method for hatchery fish, cause they don't seem to chase a fly like the nates. You have to get the fly down to them with a slower presentation. Swinging seems to work well for the nates, as does nymphing, Nates seem to chase flies more in the colder water, than hatchery fish. This is just what I have found from my fishing experiences. But In the summer, when the water is warmer, Hatchery steelhead will chase a fly, and swinging works well.
--good luck
--Mike Korenko