You only have 7 posts, RobRoyce! I don't think you are annoying anyone ;-)
Carbon fiber? I usually buy fiberglass screen at Lowe's/Home Depot. The size of the holes is not usually an issue for the drainage as long as it's window screen. It's mesh coverings over vents where the size of the mesh matters more because you can have mesh big enough for fruit flies to get out. For drainage, you are just trying to keep the substrate from getting down into the drainage layer. Most common window screen is just fine for this purpose. Just steer clear of the metal stuff.
Mark