RE: covering cowling
Man, don't you miss the "bananna oil" smell of the old Aero Glos paint. To many almost choices today.
Testing the paint before painting your model is very good advise. It's a lot easier throwing away a pice of scrap cardboard than trying to salvage a screwed up finish on your model.
If you find one combo that works, stick with it. The Krylon Fusion has a primer, several finish colors and a clear glossy top coat that are all compatable with each other, and if you let them set and cure long enough, they are hot fuel proof. It's when you start mixing brands, or even different lines in the same brand that you start to get yourself into trouble.
I remember from almost 60 years past, "MOM how come I have to learn things the hard way?" Looking back, those are the leasons I remembered. A lot of the easyones have slipped by the way side.
Don