I'm afraid I can't help with the fly selection, but a couple of areas you could try are the west end of the lake (closest to town) and around the Bonanza Resort (talk to Bruno, the owner, he's a fly fisher) and along the shoreline west of there to maybe a couple hundred feet from shore, this time of year probably best to try early morning and into the evening. That way most of the yahoos with their jetskis and ski-boats (there weren't too many of them last time I was up there fishing, couple of years ago though) will be either still in bed or have the boats tied up for the night, and the fish will be coming up from the cooler/deeper water to feed. Probably a couple other decent spots, but those are the two I would recommend for pontoons, lots of places to get to shore in a hurry if need be.
Tight lines