Back to the paint shop!
The light grey undersides are masked ready for the green upper surfaces; for this I used Xtracolor X-351 Japanese WWII Army Green. It will have a couple of lighter shades of complementary colours before the weathered paint-look is finished, aside of any washes etc later on. I left the JAG overnight and then mixed up a lighter shade of green – X110 Forest Green; working this with the airbrush into the panels and exposed upper edges/surfaces. You can see the slight contrast in these pics.
The wavy camo demarcation line is sprayed freehand, but you can use Bu-tack putty masks or another method of course. The trick if there is one for this type of spraying is to keep the paint well thinned and come in close with hardly any back pressure on the trigger to control the air/paint flow. Pressure is down to about 15psi.