It is very possible to hand paint them (aircraft 1:48, 1:72) all through. That was the only way I did my models when I still lived at home. All I had then was the small testor enamel bottles.
My best advice is to record paint to thinner ratios for each color. I vaguely remember I only would thin Alum 5:1 (paint:thinner), but gloss black was 2:1. I recommend practicing on scrap with each mixture before painting the real deal. I always had to tweek the ratios a little each time depending on the humidity, heat, etc. Otherwise I would get brush marks everywhere, or the paint would pool in depressions, or it would be too thick or....
I don't know about the final gloss, flat, matt coat. Never did did final coats back then. Now I spray all exterior paint & future with my airbrush. I still handbrush all interiors & details.
- Jamey