This is what we are tying in anticipation of Autumn fishing; its a pattern my buddy Vincent came up with some years ago that works quite well. You can tie it as shown, or wrap some wire weight along the shank to give it some mass so it gets down quickly in the fast runs and pockets where the naturals are found. I tie it both with and without weight - for the weighted ones I tie in a short length of red thread on the bottom of the head so I can tell which is which. If you like to fish two flies, a weighted Iso nymph is a great anchor fly. For your dropper fly, go with something small like a pheasant tail, RS2 or some other midge pattern you have confidence in.
Any 2X long nymph hook in sizes #10-14 will do. And yes, I used 6/0 Danville black thread......sometimes you have to give the olive thread a day off.
Sharpen your hooks!