Varying amounts of split shot are added to make sure the yarn fly drifts through the run near the bottom, in the zone where the steelhead lie. As a general rule, fish yarn early in the season and when sight-fishing for trout near their spawning beds. I prefer brightly colored yarn unless the water is very clear, which is rare for the Root. Productive colors included chartreuse, orange and hot pink. You can combine one of these bright colors with a softer color in infinite combinations.
Some folks use a vise and pre-tie the yarn on the hook shank.
I use a snell knot and slip the yarn through the loop as I fish to find combinations that produce strikes. Local patterns vary, but I've learned that darker patterns work well on the Root. Fish nymphs, streamers and wet flies later in the spawning run, in deeper pools and especially after the suckers enter the river. Suckers will dominate your catch when fishing yarn once they move into the river. Whatever your methods, you're bound to have action if you can find fish in the river and you are persistent.