Famine: Finally, I have granted your wish. The Green and yellow clone are complete.
DualSaberMaster: I masked some of the larger areas with tape, but that only works so well because the paint bleeds underneath and makes a mess. So basically, you have to go back with an exacto and make adjustments by scraping away the excess once it's dry. Dame with the battle damage to the paint, I just scrape it with an exacto when it's finished, taking special note around the edges and other high points of the armor that would show wear first.
As for the "dirtying up," I just dry brush certain areas with black, sometimes grinding and smearing it into the surface with a finger. Again, I pay attention to the points real armor would dirty up first.
All paint I use is Tamiya acrylics.