Marinaro used a ball of dubbing where the wing is attached. The hackle could be wound around the ball. I believe he suggested wrapping the hackle with the short fibers behind the wing on the top of the hook, but in front of the wing/ball when under the hook. The hackle with the longer fibers was wrapped in front of the wing on top of the hook, but behind the wing/ball under the hook.
I don't see this clearly in Byron's example, even though it is a beautiful fly.
The reason for this hackling method was to tip the head down and the butt up. Real mayflies don't drag their tails in the water - often their abdomens don't even get immersed. This is the profile Marinaro tried to present. See 'A Modern Dry Fly Code', pg 77.
And Byron, on page 251 and 252 he does use fur.