Yellow I see as a hopper color... I see a lot of hoppers around here that would be imitated best with yellow foam. I would tie bigger hopper imitations in yellow and tan, smaller sizes in tan and chartreuse.... and consider it matching the hatch. Black I have found particularly effective on certain bodies of water, and also find a lot of crickets in the same areas... so more of a match of a food source than something oddball. What I was refering to in my first post was how something "outside the box" for you is a "realistic match" for me, using the same or similar patterns. Now I also know you aren't tying to match hoppers, but golden stones most of the time too, which makes a big difference!

So if all of the flies were equally effective, would you rather use a fly that is more of a match to the natural, or one that is super easy to pick out?