Jax Brown-Black is the product we would recommend, but you may have a major stumbling block in the removal of the lacquer on the new doorknobs. Chances are the clear lacquer over the brass is epoxy based, baked on or electrostatically applied (or a combination thereof). The Jax Products will only work on the metal itself so the clear-coat will have to be removed – we have nothing that will help you remove this type of lacquer. IF you are able to remove the lacquer, Jax can help with the rest, but you will have to experiment to achieve a color-match, and Brown-Black is the most versatile option here.