Just a little history that I know about. I was present and accounted for at the West Denver Fly Show in the mid '70's when Dan debut the fly. I'm gonna guess this is the first time anyone had seen it other than his buddies.
My Bud came over to me and said "Come here, I want you to see something". We were front row at Dan Byfords tying table. Dan was kinda a bashful guy and had a partner who was doing most of the talking. He say's, "OK Dan why don't you show 'em that new fly". Dan started grabbin' stuff and wrap..wrap.. clip clip he was done. I looked at my bud and said "Whew.... he's quick". Dan Byford was quicker than a speeding locomotive on the vise, that's what was impressing the folks watching him tie.
Our little group was already using the "Rabbit Matuka" at the time and did'nt think of his new adaption as an invention, but Dan didn't go through the extra steps lashing down the wing material used when tying the Matuka. He also managed a mylar body that had a belly. I think the fly appealed to the guys who liked to tie 'em quick and easy.
New Zealanders can not exactly toot their horn over invention of this style either. There are fly patterns described in history that will go back to native American fisherman fishing skin strips millennium ago. I will give them the fly tied with the Australasian Bittern bird feather because the bird was indigenous to the islands, and thus called a Matuka.
So how does a fishing fly gain so much notoriety, The local outdoor writers are responsible. One article in the Denver Post or the Rocky mountain news will send a herd to the fly shops. Especially if some nationally know fly fisherman is mentioned in the story. Like "Lefty". And that's the way it is.
Winning a one fly competition on the Snake will also catapult a flies reputation as Scott Sanchez's "Double Bunny" was able to capture the attention for it's performance at Jackson Hole's contest. The "Zonker" is now world wide terminology and is at least accepted as a style of tying by everyone.
And Greg, excellent tying instructions on proportioning the materials relative to the length of the hook eye. I think we can all benefit from that instruction.
"As far down the river as he could see, the trout were rising, making circles on the surface of the water, as though it were starting to rain."- E.H., The Big Two Hearted River