The colors I used is actual flat white, and OD green. I sprayed the white on, not trying to make it thick, leaving the "edges" more grey from the black undercoat.
Then I used an "over-spray" technique to apply the OD in a mist in a cross pattern down the middle and eyes. I covered the eye holes with tape before hand though.
I couldn't find my brush, so I used a paper towel with a bit of flat white on it to streak the exact center for a highlight.
The streak dried fast , not letting me blend it so well... , but it does the job as a highlight though.