A couple of points:

Some colors of Rustoleum are reportedly NOT fuel proof. Mostly metalics. Check before using.

I believe the spackle mentioned is the Lite version, not the normal heavy stuff.

Nitrate is not fuel proof and must be covered with a fuel proofer such as Butyrate dope, polyurethane varnish, etc. Also never try to put nitrate over butyrate. Nitrate adheres well, doesn't shrink, dries fast. Butyrate shrinks (unless you get the low shrink kind) and is good for tightening fabric covering. It is fuel proof but takes a long time to completely dry. Although usable quickly, it will continue to "gas off" for weeks.

That said, I mostly use butyrate. I have had best luck with Brodak butyrate dope, which is a derivative of Randolphs, especially formulated for models. Other brands work well too. I just prefer Brodaks because it dries faster and has has more pigment in the colors.

George