You are right about the Catskill stuff. I still have some Dun Variants and Gray Fox Variants tied by Elsie Darbee and they are as you would expect...pure Catskill in style. I believe the Dun Variant was a Darbee creation to imitate the Isonychia mayflies...aka Slate Drake. The Gray Fox Variant was to the best of my knowledge created by Art Flick as a Green Drake imitation, along with his BWO which was nothing but a small variant.
The Hairwing Variants I received all those years ago from Bailey's had the white calf tail wings but over sized...almost spider like hackle, and the wings did not protrude outside the length of the hackle...which means they would have been easily visible only to the fisherman. Like I said before the hackle, body and tail were all on the very dark gray side.
Like so many things, without any proper records or paperwork to confirm any of this we will probably never know the true answer. We've seen this in the salmon flies we tie..the changes in patterns from Francis to Kelson to Pryce-Tannatt as examples. Materials, proportions, style...they have changed dramatically over the years.
Great stuff and a fun discussion!!!
Cheers My Friend,