First off it does not get as hot in the Winds as in the Sierra so tighter weave material too hot for the Sierra is fine. I rely more on having my clothing loose, so there is air space between the clothing and my skin. I have had good luck with technical climbing pants (Schoeller)but I buy them one size larger. I wear over-sized nylon long sleeve hiking shirts (like Columbia). I have not tried the "bug-off" clothing so cannot comment. I avoid skin-tight T-shirts. I also wear long gaiters (pack cloth weight nylon) all the time so flies cannot get up my pant legs. Since there are a lot of dewey mornings, they also keep my legs dry. I never go any trip without a head net. A loose wind shirt over your hiking shirt also helps. I bring a pair of canvas cotton garden gloves to keep mosquitoes off the back of my hands and also keep hands from getting sunburned and overly dry.

Mosquito season in the Rockies is shorter but can be more intense than in the Sierra. I really have not had a lot of problems with horse flies- but then I do a lot of off-trail where there are not many horse flies.