Troll Skin

I have been painting my trollbloods the typical troll color in fantasy, flat out green. But im not a huge fan. I started using a lighter color, with only a hint of green. Check them both out:

Now neither are obviously done, so dont judge them by their complete looks, just let me know your opinion on the skin color (while you are at it, how is the tartan?). The green one hasnt been washed or highlighted at all, the lighter one has been washed but not highlighted yet. Im wanting to go for more of a "realistic" animal feel with the colors, more reptile like, kind of. So I was thinking of maybe doing the big beasts in grays like Rhinos or elephants. Any ideas? Any suggestions on colors for the troops? Thanks!