I often wonder about how exact I have to be compared to the real thing. I mean, the current is moving quite fast, even in a slow stream, and a fish doesn't have much time to make a decision whether to bite or not. When something is moving so fast, I would think that color discrimination isn't so good. I'm tying a lot of very small midges right now (22,24, even 26) and I wonder how they can even see them in the current. Still, I have had good success with BB's and miracle nymphs and I'll keep on making them in quantity. Those trout must be amazingly well adapted insect eating machines to see such tiny objects in fast moving water.