I am not a fly fisherman but I do a lot of white bass fishing. Over the years fishing Table Rock, Stockton, Pomme de Terre and Bull Shoals for whites I have used a lot of color combinations. I am using jigs but I imagine that the color schemes should be close. I carry at least 20 different color combinations when I am strictly fishing for whites.
Any color can work on a given day. For example, I put together a lime and lavender jig one day and nearly puked looking at that ugly beast. I fished it at Pom for 2 hours with narry a smell. I put it down and didn't use it the rest of the day. The second day I started out with it and after an hour the guy in the front of the boat was asking if I had any extra as I was giving him a severe beat down that it.
My theory is show them something that they haven't seen before and you may get a pleasant surprise.