I think size is more important than patten, especially that time of year when water temps can vary dramatically. I carry a variety of sizes, 1.5 through 6.
I'm racking my brain trying to recall a patten that hasn't worked on the Ronde at some point. That said: green butt skunk, max canyon, silver hilton, burlap, boss (black and red,) rusty rat, dark daze (Mike Kinney pattern,) coal car, signal light, they all work... If I were to limit myself to two or three pattens that time of year, it'd probably be something along the lines of the max canyon, and the green butt skunk, with perhaps a silver hilton for back up.
I am by no means an expert, I have fished this river for over 30 years. I used to believe color and size was all important. My experience has been fish a fly you have confidence in and stick with it. Look for the water which you believe a Steelhead would like and fish it well. As far as I am concerned the speed which a fly swings across the water is far more important than size and color. In 2009 which was an incredible year in terms of number of fish I worked the lower river from Shadow, Turkey, the Elbow and the Rock Garden multiple times and caught fish in each run and never used the same fly. That was an unbelievable year, nevertheless what it taught me was if the fly is presented correctly a "player" will grab the fly.
G, i was the young guy you gave the pep talk to below elbow (lone tree) . That little bead head fly you gave me is still sitting on my tying bench now. I had to get out of my winter run tactics and think summer run (small sparse flies). To the original poster, go small even 10s & 12s and find rested water and you will find fish. Swing, swing, swing and it will pay off. Good luck I'll be there in October with the rest of the world swinging away.
You're right about fly patterns or color for steelhead whether in the Ronde or for that matter any other steelhead river. However, trying to convince folks with less experience this truth is futile in my experience. Size and more importantly presentation do the trick, not some majic pattern or color combination 98%-99% of the time.
You are wise beyond your years....... It takes time for many to understand what you and I already know...... I will be down on the Ronde about 20 days this fall. Regardless of the number of fish over the last dam (Lower Granite) I am confident I will catch fish and if I want each could be on a different fly........