This has been kind of a timely thread for me as I've been increasingly interested in tying some of the old classics as accurately as possible to the original.

Muddler Gapen_Muddler.jpg in Bates' Streamer Fly Tying & Fishing and reportedly tied by Gapen.
It's from the 1995 edition but the same tie is shown in the 1950 1st edition.
The head remains fairly loose but a lot fuller than the original fishbum posted.
Did contact Bill in case no one else did to see what he has.