Any tips on masking a 72 dart grill for paint?

Tricky! get some 1/4" masking tape and some 1". I think I did the black first on mine, then the silver. Just remember to take your time and go slow. It'll pay off when you're done! if you do it right you'll be blown away! (Check out my avatar!) Too bad we weren't closer, I'd pick it up and paint it and charge you very little, maybe in exchange for car parts! :)
Good Luck!!