Tied these up the other day on a size 16 orvis tactical hook. They really work great as anchor flies to get your rig down.
Bead to match hook. Any color. I use tungsten for weight
tie in green or olive wire
green UV dubbing tapered up the hook
black UV dubbing for the head.
Trim fibers on top tie in orvis thin skin http://m.orvis.co.uk/p/thin-skin/8a01
pull tight over whole fly. And wrap wire rubbing up the hook shank tying it off at the bead.