Very nice ...
... and I can testify to the effectiveness of the FEB ( furled extended body ) flies with almost ten years experience with them in various sizes and patterns.
If you go to the FAOL Fly of the Week archives at 6-18-12 for Duck's Green Drake, you will get an idea how to incorporate tails into your extended furled body flies.
Moose hair is a bit too stiff for a good effect on size 18 flies because of it's resistance to the furling process, but works well on larger flies.
My experience is that you don't really need the tails on the smaller flies, but they are a nice touch, and I do think they really enhance the effectiveness of the larger flies.
John
The fish are always right.