Mount a Hanak H260BL in size 16 with a 2.0mm copper tungsten bead. The hook is one hook size short in the shank, so it gives a size 18 body with a size 16 gape. A real benefit for holding fish on a small blue-winged olive.
Start dark brown UNI 8/0 behind the bead. The thread is chosen to disappear into the head at the end.
Select four or five Coq de Leon fibres, keeping the tips lined up. Pick a feather barred all the way to the tips. Only about four millimetres of tip actually gets used, so a feather that runs light in the outer third is wasted on this fly.
Tie the fibres in with a few loose wraps with the tips well past the bend, then pull the butt ends towards the eye to shorten the tail down to about one body length, check it, and lock it in.
Clear the butts and tie in a fine copper wire rib, then wrap back and park the wire in the material clip.
Prepare the Condor Substitute: choose a straight fibre rather than a butchered one, go about an inch down the fibre and tear the tip off, so the tie-in point is where the taper and fuzziness begin.
Tie the fibre in by that point. Kevin Compton, who created the fly, ties in one at a time; Tim ties in two at demos because the material breaks like peacock herl and the second one is insurance.
Wrap the thread up to the bead, then back part-way and forward, and back again a shorter distance and forward, building a very slight carrot taper. Keep it slender. That is what makes it read as a baetis.
Wrap the Condor Substitute forward in touching wraps, using fingers rather than hackle pliers for better control of the pressure. Back off a turn if a gap opens, then tie it off at the bead.
Counter-rib the fine copper wire forward through the body to protect it and add shine, then helicopter the tag away.
Dub a very tight, very fine noodle of peacock bronze Siman dubbing and take about two turns tight behind the bead for a small dark head.
Go straight into the whip finish, the dark brown thread vanishes into the head, and trim.