Start the Yellow Veevus 8/0 on the hook and leave two tag ends hanging off the back; two strands split the tails better than one.
Flatten a section of the 30-50LB Mono with pliers, about one shank length long. Bind the mono in right at the flat point and take a quick whip finish so the hook can be reversed in the vise.
Reverse the hook. Coat the mono with a light layer of super glue, press the thread tag ends to the underside so they stick, then jump the thread onto the mono, spiral it out to the very tip and back down to the hook to build the extended body.
Take four Dun Mayfly Tails, about a body length hanging off the back, and capture them onto the extended body, working out to the tip. While there, split the tails by sneaking the thread between them. Spiral back down the body and take a two-turn whip finish; leave the thread attached so the hook can be reversed again.
Reverse the hook back, trim the excess tail butts, set the split just as you want it and give the tails a second dose of super glue now, before the hackle is in the way.
Capture the White Z-Yarn on the hook, take a small X-wrap to start it, draw the fibers together with one loose wrap down to the shank and back, then a couple more wraps parachute-style but not as high up the post.
Bind in the Dun rooster hackle at the post, then dub the thread with just enough PMD Superfine Dubbing to coat it and wrap a slight body over the thorax.
Spiral the hackle forward through the dubbing three or four turns, capture it and trim the excess.
Take a quick whip finish, draw the post up together and trim it just a little longer than the hackle.