I was there last week. I chatted with Trey Prater(guide at beavers bend fly shop) and he said following:
"We have a lot of sulphurs and caddis coming off along with the sporadic emergence of various other mayflies. So your pheasant tails, soft hackles, and bwo emerger patterns in sizes 16-20 work best. For dry fly, can’t go wrong with an elk hair caddis or parachute Adams in same sizes as mentioned for the nymphs. Spillway creek has the least amount of tourist on the banks but evening hole through cold hole fishes well when available. Good luck and tight lines out there"
I had some luck with some small RS2s in the olive color and small pheasant tails. I mostly fished spillway creek(upper side) since the evening hole/bluffs were super crowded with people swimming and such during the week. Fishing was tough to say the least though, although still a noob here, so I was probably doing something wrong
hope this helps.
Edit: i guess im a little too late to this thread... sigh anyways leaving in case someone else needs the info.