I was up there a couple of years ago. I do remember the Golden trout being a little picky but once we figured out what they were after we didn't have a problem catching them. Ended up focusing on very small terrestrial flies like ants. We didn't bother trying to fish the upper lake when we went because we had heard there wasn't much for fish.
I shared my visit and a lot of pictures here if you want a read:
https://www.stringtheoryangling.ca/m...-alberta-2017/