Spent CDC Flies ca be tied very easy if you have the proper CDC. Here is a version that I like to make to imitate a spent ephemera and is tied only with CDC barbs (means barbs stripped from the feather stem).For a size #14 I used the barbs for 3 feathers to make the wings. Some guys consider it too dense but I fish this fly very often on rivers from lapland when big grayling and trout eat after midnight. I need it to floats perfectly on strong currents and to be durable when strong fish fight!
I use the following materials:
*Hook: Maruto D04 or Demmon D400 BL
*Thread: White 70 DEN
*Troutline Peacock Quill Hand Cleaned in different colors, yellow is my favorite one
*Tail made of Coq de Leon
*Thorax: Squirrel Dubb in natural color
*Wing: CDC dark grey selected feathers