That beige is such a tiny part of the pattern that I omitted it when painting my 28mm marines. I reckon that in 20mm, it will seem too prominent and make the pattern look more like the old woodland or an attempt at Multicam. When worn in humid and dirty environments it’s all going to tend to a muddy khaki and the tiny beige bits are invisible. Google Marpat tropical and you’ll see what I mean. That said they look well painted.
I’ve always thought Marpat looks a bit like Jackson Pollock trying out dog shit as a painting medium. Stippling the pattern is what I did in 28mm, whether that’s an applicable technique in 20mm I don’t know.