You can never have to much Liquid mask, so Id buy the big jug. (Esp. if ya plan on painting a few lids). But yeah, as far as the sections, draw your scheme on the outside of the lid. Then smear on the liquid mask, then after it dries (Id do at least 3 good coats) it dries pretty clear and you can cut out the design (Exacto knifes work slick) on the inside threw the mask. Then peel away the ones ya want to paint. Be sure to post up some pics of your work! Youll like the liquid mask. Its some good stuff!