Years ago I had a real hot spot for the green drake hatch that's gone now presumably due to pollution. At dusk the spinners would make their mating flights and at a point where it was hard to see they would drop to the water and the big browns would start the feed. There was absolutely no question that they were after the spinners, greedily and in large numbers. I had trouble matching it for a long time till I learned to tie them over sized.
I don't recall anymore what size is best. I would say try tying them on a #8 or #6 hook. Teflon's pattern is probably as good as any tho there are a great number of patterns out there which you can find thru a google search.