Here are some pictures of black-painted grey mesh:https://www.celicahobby.com/photos/celica/installs/inst_lower-grill/
You might even want to go with a tighter weave than what was used in that link.
If you are doing it custom, purchase enough mesh, that you can paint a portion of it black and keep another portion as grey. Then you can test-fit it and see what you like the best, side-by-side.
Now you have three option to decide; if you want to paint it gloss-black or flat-black or not at all.