I painted my frames with epoxy, then sanded with the ROS on the flat parts, and by hand on the edges.  Despite my best efforts, it looks like I sanded through the epoxy.  At least, the wood got considerably lighter in certain patches.

Not a big deal.  I expoxied the bare spots, trying to make the thinnest coat I could with a chip brush to minimize sags and sanding.  I sanded those spots just enough to eliminate any shiny spots in the epoxy, but it went through into the wood again.

Do I continue thin coats of epoxy and just accept that it'll take three or four attempts to coat each part?

Should I use thicker coats, and try to sand the brush strokes smooth without sanding through the previously-sanded epoxy at the border between the previous round and the new?

Can I leave minor areas without epoxy as long as I varnish over them before taking the boat out?

In some places the epoxy feels smooth, but I can still see shiny areas.  They disappear when I rub it down with denatured alcohol.  Is it okay to leave like that?