The only way to paint with them, is avoid them
. I have tried; is basically madness try to get any good result. If everything is primed with white, and you buy good quality artists acrylics, perhaps. I remember using my mother's acrylics to paint black, yellow and blue for my Britons, sometimes the black was not that bad, and the blue with two coats gave a different look.
Some years later I tried yellow out of desperation, it was bad, but mind, not that different to other yellows properly sold as modellers paints!
For me, coverage is basic. I hate having to prime, or paint two coats.
Denyer, very interesting recipes
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Personally, I use a mix of nearly all manufacturers, Humbrol, Vallejo, Game Colour, Citadel, P3, Coat d'arms, etc. For what I have seen, Formula P3 yields the best results, but some colours are just very bad in coverage. I would say that the old Citadel/Games Workshop were the best paints, in excellent coverage and super vibrant colours, but alas, not made for the last 15 years more or less.
For varnish, MIG super matte is excellent to achieve a good solid matte finish.