I am glad I was able to help. Those are some great pics! Did you make it up again this weekend?
I saw the same bugs on Saturday that you posted pictures of. Unfortunately, I am only familiar with the nymph stage of Isonychias--I have never seen the adults. But they certainly were large mayflies. My dog kept snapping at 'em as they flitted by. The one I looked at up close was burgandy colored. I didn't get any pictures though.
Thanks for the suggestion for the FAQ. I will try to get something in there as soon as I can.
Dawn