Garrett, that base green is spot on... But what I'm talking about? The whole helmet is (already) a masterpiece! I can't wait to see the mandibles and the rim painted to see the the new color combination and its effect.
The weathering under the killstripes is actually silver with base green painted on. More exactly, when the helmet painter removed the tape that he used to do the killstripes also removed (accidentally) some of the paint layers to reveal the silver underneath, so he used a brush to 'mask' those areas.