This fly is a Steve Thornton pattern. I like tying these up although the varnishing is time-consuming and in the future I may invest in some UV cured resin to see how that works. I use this fly mainly as a stalking pattern, but I wouldn't hesitate using it in a small Stillwater. As a rule I tie these up without colour and use various shades of permanent marker to colour just before varnishing. Predominantly I would use a watery olive, grey tones and a subtle pink.
As a thought, and something I may try in the future, would be a spun loop of say, squirrel guard hairs or something similar laid along the bottom of the fly, trapped by the thread in the same way as the hen hackle.