I'm at the washing stage of a A.M. Avenger in a Dark Sea Blue finish and am not quite sure what color wash might be a good fit on the dark blue. As I rule I usually try a shade or two darker than the base coat, but I don't think black will show up as well. Maybe go lighter? I've thought about a "zinc green" but I've never seen the green show up on panel lines in pictures before. I use oils and mineral wash.