A couple/three years ago, Fly Fisherman put out a little called "Getting Started in Fly Tying."

An article on may fly proportions had this to say:

Duns...

Wing = Tail = Hook shank length (HSL).
Collar = 1.5 x hook gape
Body = .5 x HSL

FWIW, I usually put my wings at the 30% mark from the eye and make the body to the point where I have enough room for three turns behind the wings. So my bodies are probably more like .6 x HSL


Nymphs:

Body = thorax = .5 x HSL
Tail = hook gape