I've only ever read of grayling, having never fished in waters which hold them. Although all the flies you've listed are weighted nymphs, they will take flies higher in the water column (and even dries) will they not? They must, at first, feel to be a much larger fish given the huge dorsal fin on them. I envision them turning sideways in a current and the resulting weight magnifying the fish four fold. But, as I say, these experiences are all from my imaginations and may not apply to your world!

- Jeff