I love the Wilson, consider it my home river. I fish it a lot in the winter and a few times in the summer. Fishing for summers on the Wilson can be difficult due to the low clear water. I'm sure you know that smaller, darker offerings are key, but there are other factors that come into play, especially on the Wilson.
Your best bet is to get there early, before the summer sun hits the water. Once the sun hits, the steelhead lose their natural cover and become too nervous to bite. Look for deep holes where steelhead can hide and feel safe. Fishing pressure also turns off the bite. Just because you only saw three other fisherman out there doesn't mean that these fish haven't be pressured to bite. Those same guys may have been fishing for the same fish earlier before you.
If I were to fish the Wilson for summer, which I may try sometime soon since we are expecting rain, I would use bait and fish at first light. Keep your offerings natural. Good luck and report back.
Tommy