The link below shows a pattern that would imitate the one you photographed fairly well, and isn't hard to tie once you get used to the legs. I haven't fished them on the Clinch but have used them on other tailwaters with success. Its the pattern I used when I see smaller crane flies present.
This next link is a more realistic pattern and I sometimes tie it to represent the larger crane flies I see and isn't a lot harder to tie than the first one. They both will work well in any size you want to imitate.