I've never tried the bubble with fly, but I'm guessing it would work great. Alot of these high country lakes, you'll see the cutthroats just cruising mid-day, looking for an opportunistic meal to sip off the surface. While I've never thrown spinners up here, I'd imagine a bubble with a small dry would definitely work. The key with trout, they feed primarily by profile identification, not motion. At least for dry flies. They are not like bass or bluegill, where making ripples and motion on the water attracts them. Trout will come up, if the artifical fly looks real, they'll take it. If it doesn't, they'll turn off of it.
I usually leave my fly rod in the truck, as I have a tendency to not want to stop fishing
I usually leave my fly rod in the truck, as I have a tendency to not want to stop fishing