2 oz. covers a lot. Even if you're doing a single-color scheme, a bottle that size will do more than one lid. You can thin it if you want. With some paints that will help the atomization and coverage. If you use Faskolor, I would recommend thinning it with a bit of water as they are typically a bit thick in the bottle. Racing finishes (Pactra) and Spaz Stix are pretty thin and usually can be shot as-is. General consensus here is to stick with either Pactra, Createx or Spaz Stix for ease of use. Water-based (Pacra Acryl or Createx) make cleaning just that much easier, too.
If this is your first attempt, take some time to practice. If you get a 2 liter clear soda bottle and cut it in half lengthwise, that gives you a bit of a practice canvas and will help you get some brush time before you try a full-on lid.