Lovin' this thread. Lots of ideas. I was using a soft-hackle fly like Mark K's, same hook, except tied with black thread, yellow floss (including shuck), and olive-dyed badger (with a wrap or two of opalescent olive petite estaz just behind the hackle. Was killer in a certain lake I know with wild cutthroat. Otherwise, i've been using black soft hackles fished in the film, to imitate the black gnats in another local lake. When I first fished that lake, a local told me to use "small black flies." One memorable day, a trimmed down #12 Dr. Spratley fished in the "film" blew my mind... first fish was an 18"er that socked it moments after it sunk in the wind chop. I have to add that a nice little wind chop on that lake makes the fish less cautious.