That fade on the checks is awesome, was it done with pre-shading and a tint after?
Aye, heavy green at the bottom, lighten it up, it doesn't matter too much if you lighten it scrappily at this point as you go over half of it with the other colour checks. Then use the lightest colour you left off at on the shading stage and start drawing in the checks (individually, mneh) right in the darkest shaded part, and lighten the checks any way you can on the way up hehe. Usually I sketch them out in the darkest shade then lighten them towards one edge as I bring up the paint mix. Hope that makes some sense man :)