Slide the Umpqua 2.8mm copper slotted tungsten bead onto the Umpqua 400 BL and start the Camel 8/0 thread well behind it — leave room, because this fly carries an oversized thorax, and that gap doubles as your marker for where the quill ends.
Counter-spin the bobbin to flatten the thread so the abdomen stays thin, then tie in a few Spanish Coq de Leon Pardo fibers for a tail a full shank length long and trim the butts.
Tie in the stripped BWO peacock quill at the back — tying it in there rather than at the front avoids crossing it twice and building bulk — then wrap the flattened thread forward in touching turns and put in a half hitch.
Grip the quill in hackle pliers and turn the vise sideways so you are pulling straight rather than left and right. Take a very light first wrap, then tighten as you wrap forward; catch it with a drop wrap, a couple behind and one in front, and cover the last wrap.
Coat the quill with a thin layer of Solarez — enough to protect it, not enough to thicken the body — touching it right in at the tail so the transition from quill to shank stays smooth, and cure about 10 seconds with the torch.
Trim the butts of about ten strands of Opal 1/100 Micro Flashabou square and tie them in right behind the bead, wrapping back to about the hook point so the quill body still shows.
Spin a very thin inch-and-a-half noodle of Olive Brown Hareline Dubbin, picking the longer guard hairs out, and wrap it forward from the flash tie-in point to build a deliberate ball of thorax — bigger than an average thorax at this size, shaped rather than blobbed.
Tie in four or five fibers of Olive Brown Z-Lon for legs, catching them on one side and bringing them around to the other; the softness is the point, stiffer materials do not move in the water.
Continue the thorax with an equally thin noodle of Chocolate Brown Hareline Dubbin up to the bead, stroking everything back and tapering it up to the bead.
Pull the Micro Flashabou over dead centre as a wing case, fighting the Z-Lon legs out of the way; hold it with a drop wrap, pull down tight when it is centred, then one wrap behind and two more in front to lock it. Trim it as close to the bead as you can.
Dub a small chocolate brown collar over the trimmed stub, wrapping in front of it so it folds back and locks down. Whip finish a few turns, trim, and put a little UV resin on the thread only — not enough to saturate — then cure. Trim the legs off at the back of the body.