Most use enamel I believe. Should be several paint threads in the armor section, but you may have to dig. Stormtrooper guy has a great one for rattlecan paint up, If you haven't checked his out, make sure you do. His paint up looks really pro.
As far as the gaunts, I'd use cabernet red, which is in his tutorial and also a spray can, but ya gotta get the black primer missing to have the color come out right. Don't want them too red.
Several good ROTJ paint ups. Some with air brush colors, some with spray, some with both. AFFO$ has a great one and it's stickied.
Check out Necronaut's ESB build tutorial for the gauntlet shells build up. Will give you a very good idea of some preferred method on these.