I've seen as many or more rusty spinners on the water as I have olive. While I appreciate what is written, and I'm not trying to argue here, my experience is from being on the water and seeing it for myself. I once found myself on the Teton River outside of Driggs, ID in the middle of a true "blanket" hatch of caddis. The air was so thick with bugs that it seemed they flew as one mass upriver. Fish were feeding all around me. I tied on my best caddis imitation and proceeded to not catch any fish, not one take, not even a visible refusal.

I looked closer at the water and realized that while the caddis were emerging and taking flight there was also a massive PMD spinner fall and the surface of the water was covered with spent spinners in both olive (size 16) and rusty (size 18 ). The fish were on the spinners while much larger insects popped out of the water all around. I tried both flies and found the fish that evening preferred the rusty version over the olive by about 2 to 1. It was an epic night with a dozen fish to hand, another dozen lost after hooking and more than a dozen missed.

Just my observations.

P.S.: nice flies you have tied there