Start purple 8/0 at the 70% mark and wind back to the bend. Waxed thread matters on a spinner because there is almost nothing else holding the fly together.
Tie in a sparse, widely split tail of makeup or paintbrush fibres about a shank and a half long. Synthetic brush fibres are cheap, perfectly straight and stiffer than most hackle. Split them wide, because the tail is what stops a spinner tipping over.
Tie in a purple goose biot at the bend and wind it forward to the 60% mark with the notched edge trailing so each turn leaves a raised ridge. Biot gives crisp segmentation on a body this slim, which is what a spent spinner's abdomen looks like against the light.
Tie a bunch of grey McFlylon in crosswise at the 65% mark with figure-eight wraps, split it to each side as spent wings, and trim to a shank length. Flat translucent wings are the whole silhouette of a spinner. Get them level or the fly sits wrong.
Dub a small thorax of fluoro purple kapok around the wing base, kept tight. Kapok is very light and holds the fly in the film without lifting it out.
Add a small tab of orange 1mm foam on top of the thorax as a hotspot, trim it square, and whip finish. That orange tab is purely so you can see a size 14 spent-wing fly at dusk, when spinner falls actually happen and grey wings vanish against the surface.