Just an experiment. Haven't even fished it yet. But it does make me smile. Gonna have to try this at the edges of the big lake soon. The fall weather has them coming into shallow water now--on the lake--where you can catch them. And they do seem to like big flies. The trick is to make big flies that sink well, that you can still cast in the wind. Sparse and still slightly heavy. I can't remember the name of this material. The fly shops all seem to have it now. Same stuff Umpqua's 'Game Changer' streamer is made with I think. Tail is a partridge body feather chosen for maximum curve in order to impart swim to the fly--swim which would probably twist up the line if the fly didn't have a swivel built in up front.
When you do try to fly fish from the edges of a big reservoir the fishing works best when it's windy, when you fish a medium to large size fly about ten feet below a bobber of some kind. That's not an easy rig to cast. But that is the way it works best. I like to use a giant foam grasshopper for the bobber because they will occasionally bite that too. The fish probably don't even know it's windy ten feet down. But the combination of the bobber and the chop on the windy water automatically jigs the fly for you. Which makes all the difference. Without the wind you have to jiggle the fly by hand, which wears out your arm casting every few minutes.
In Montana in November it's always windy anyway.