I am a big fan of biot-bodied parachute flies for Callibaetis duns. While this style is VERY delicate, these lake trout can get very picky and I like the slim, segmented profile that the biot body provides. The parachute body rides right at the surface. I have cast to cruising fish at Chopaka and at Leech Lake and had a rejection or three before the fish finally takes the fly on the next cast in its path. I also have some Quigley cripples and spent spinners because sometimes that is what they want.
At a place like Dry Falls or Rocky Ford, the Callibaetis are very light. But as you rise higher in the mountains, the mayflies, especially the wings, are more speckled. I have two colors with me for these different locations.
Steve