It’s worth a try! I’m sure it would look good. I’d just need to do that to one black mech and then ink wash one red, put them side by side and and see how I feel about two different techniques in the same game.
Can always prime the black mechs after if it doesn’t look quite right.
I put 80+ hours into painting The Battle of the Five Armies about a year ago. Only about half done. Really need to finish that up…