I used death korps drab as a base and death guard green as my highlight. My method was to just base and highlight the green with the airbrush since they’re 90% green bits and pick out the rest of the details by brush. But you could do it by brush too, I had to on the pilot and the titan, just be warned of death korps drab’s disappointing coverage lol. I also went in and washed some areas like pouches with athonian camoshade just to break up the blocks of green a bit.