We fish Passage often and really enjoyed fishing there.
As you probably know, there are two sections on Passage, a put and take section and a delayed harvest section.
If you don't care keeping fish, the delayed harvest section is where you should go. Fishing can be excellent. I remember last year, my son and I went there on a cold morning. We hooked fish just about every cast in one spot and landed at least 7 or 8 fish each. You can only catch fish at the put and take section right after stocking, but you have to deal with the crowd and it seems the bait fisherman always outfish flyguys.
As far as fly goes, nymphing with split shots and strike indicator always works well for us. Once in a while, they'll hit top water flies at mid-morning.
Good luck, and let us know how well you do.