The Nature Conservancy has been inconsistent. With the warmer temperatures the hatches will come off in the mornings and into the early afternoons. Big PMD’s in sizes 16-18 and small Baetis are still the main players. Baetis are very small and sizes 20-24 are a must. Try a Paraspinner and a ¾ spent Baetis and fish these on 6x and 7x tippets. Green Drakes are also showing up on the slower sections. You will see some flying ants and a few beetles mixed in.
The South Fork of the Boise has been lowered to below 2,000 cfs and is a great alternative to Silver Creek. You will need a raft or drift boat to fish at this level. Caddis, Cicadas, and Adam Parachutes in various sizes should work for your surface flies.