I've got a dozen bottles of fingernail polish I get from the dollar store.
UV, Solarez thin and medium plus Loon thick.
After trying a couple different super glues have settled on lock tight gel control.
I used to like to put epoxy over the heads on some of my streamers but around a year or so ago I ran across Liquid Fusion, uv resistant, dries clear but can take a couple hours to dry and 24 hours to "completely cure". Depending on how much you apply at a time it takes two to five minuets turning to dry enough to stop "sagging". Looks as good as epoxy but no mixing.
Top three on the right are "painted eyes" then coverd with the Fusion.
Left and bottom flys stick on 3D eyes then covered with the fusion also.
BTW, if you wonder why so many of my flies kind look funky...
could be the liquid that come from under those cork stoppers