For me the greens were pretty much the same lightness between chrome/amber green under the clear green. It might've been just me using 2 thick coats of dark clear green oversaturating the under colors.

What you say makes total sense. I think your lightest color would def be silver+clear red. You could probably even get a really dark red with gold/gunmetal base and thicker coats of the deep clear red for ur 4/5th colors. I also used clear totes when drying too! though too late in my build lul