I try to save all my vacation for this time of year and start fishing it about the middle of September until the end of October. You should be hitting it at a great time. The crowds are usually much thinner this time of year, however yesterday was crowded on the canyon section.
Had a great day yesterday through the canyon. Started with dries for the first few hours and picked up a decent number of fish. Switched to nymphs for the rest of the day and caught a lot of fish (quite a few good size cutties). Different colors of rubber legs all worked well. Used a two nymph rig with the rubber leg as the main nymph and tried a number of different small (18-20s) nymphs as the dropper. Picked up most all the fish on the rubber legs and eventually just switched to using two rubber legs in different colors.
Picked up some decent browns in the skinny water. The skinny water for browns should get better and better as the fall progresses.
I also start using streamers more and more as it gets colder.
surfnsully, I have always done well there in July regardless of the time of month however if I had the choice I would go as late as possible, even postpone until August if possible. The later you go the better chance you have of being able to catch fish on big dries all day long. When the fish start focusing on those big bugs it can be crazy.
Fished it two weeks ago. The fishing was SLOW, not just for me though, also for the five other fishy guys i was with. We caught plenty of fish using various methods (terestrials, bwo's and other small dries, and streamers) but the streamer fishing was the most consistant. None of us could seem to get the timing right for the ridiculously slow take, like "God save the Queen" slow. Also, there was still a tremendous amount of people out.