I'm asking partly because scud back doesn't really achieve the desired effect in my mind.

That's interesting information. I think Oliver Edwards is on record saying that flexibody is the most important innovation in materials of the past 25 years -- or something like that. He must have a secret cache of the stuff.

Why would Fly Tyer publish a pattern that depends on materials that's so difficult to obtain?

I like those little stonefly patterns. Those little stoneflies always show up in my local sampling. Mostly I've been tying slim-bodied hare's ears for them, but I'd like to try something different.