Re: Why so many spinner colors?
I don't much bother worrying about the body color on a spinner. I always carry a small box of rusty spinners in all normal sizes and use them to match the size of bugs coming down. My theory is that the trout merely see a black or dark silhouette of the fly because of the contrast between the light sky and the fly.
I can tell you these rusty spinners work for me during almost every hatch as long as I nail down the size of the bugs coming off. Even during sulfur spinner falls the rusty spinner never failed me.
Now if I'm fishing subsurface or in the film I get a bit more particular about the fly color as I feel the trout have a far better perspective from which to see the color.