Temple Dog hair is the preferred winging material of modern Scandinavian fly-tying masters. It is very soft, provides a lot of action in the water, and slims down nicely when tied in correctly. Try a "Google" search under 'Hakan Norling' or 'Temple Dog Fly.'
A well-known fly shop in Southern N.H. has a photo of the Green Stonefly in their current catalog; don't know of any Web tying instructions
I do tie a Temple Dog wing in backwards, fold it back, and then secure with several wraps. It is not any more secure, but it helps give a 'teardrop' shape to the wing. As Mikael Frodin would say, you want the fly to look as if it might swim away on its own.
Lady Amherst, Inland,
If, as you hand your license and registration to the RCMP officer you also present a fresh hot cup of Tim Horton's and a Green Stonefly to Canada's finest, it greatly mitigates the extent of the potential fine.