Hi Byron.
I tied similar flies a few years back wanting a Humpy-style fly with a back that would stand up better to fish teeth. Tried a craft store yarn for the back and wings, then Poly Yarn and Float-Vis. I liked it for smaller sizes because you could leave the fibers as long as you like and trim to final length after the wing is divided. Also, if you don't want the back and wing the same color, you can use white and color the back with permanent marker.
Great looking fly!!
Arnie