Yeah man if you're seriously going to do this, I'd go with at least a Duracoat finish. Rustoleum on BNVD? Man that just ain't right.
OK under anything you should know. In case you're really serious. Put cotton balls over the lenses. Mask off with good masking tape. Cover data plate, small windows (if you got them), and possibly dove tail interface.
Wipe it down LIGHTLY with a quick flashing solvent, such as laquer thinner, or brake parts cleaner. A little on a lint free rag to remove all grease n dirt. Then scuff it up with green scotch brite. Give the paint some tooth to stick to.
Mount the thing to something you can spray it on. Ideally it is suspended in the air so you can spray around it. A piece of wire from the garage ceiling (I use my heavy bag chain), with a pipe cleaner on the end to wrap around a convenient spot (perhaps the dove tail interface).
Shake the shit out of the can. Test spray on some scrap cardboard. Establish what distance you need to be at. Too close it will sheen and possibly run. Too far and it will orange peel or dust coat. (I like the right one btw.)
Spray in light passes, hitting it from multiple angles, turning work as you go. Stop when it sheens up and let it flash off. Let this first coat dry. Come back and inspect (in broad daylight is best). Lightly touch up as required. Lightly sand with scotchbrite to even out coating, especially if you have any shiny build up. Lightly touch up if required. Let this set for at least 24 hrs. 48 is even better. As an option finish with a clear flat coat. Remove masking and cotton. Re-clean lenses. If you can, don't fuck with it for a week. Or if you're like the rest of us, go head and re-assemble covers on it, snap into mount and check it out on your helmet.
Man I hope this wasn't a big send up.