Clamp the 15 mm shank, lay down a GSP thread base, and create a dubbing loop at the rear.
Load the loop with tapered flash (silver/Moonlight/pearl, roughly 60/40 to the back), spin it into a flash brush, and wrap it forward over the whole shank in tight, well-spaced turns to build a high-profile flash tail; comb it out and whip finish.
On the main hook, lay a thread base, tie down 40 lb mono, thread on the beads (one red between two), and form a loop connector to the shank; wrap the mono down over the top, glue, and secure so the shank articulates freely.
Form a second dubbing loop and load it with a shorter, tapered flash blend (moonlight, silver hollow, pearl, plus a few red strands), spin, and wrap forward past the hook point, brushing back as you go.
Build one or two more dubbing loops of progressively shorter fibers to taper the body up toward the head, keeping everything sparse and combed rearward so it doesn't foul.
Whip finish at the head and tidy it up.
Comb the whole fly out to a high, roach-shaped baitfish profile and add a drop of glue to the head wraps; add eyes and a UV coat to the head if desired.