We use rustoleum smoke grey straight from the can, but our machines are work machines. Most important thing to remember unless you use oil based the paint won't stick to any residual oil left behind, and it won't get hard either.
Black, straight from the can. Won't *really* get hardened up for a good two weeks or so. Typically two coats, disposable foam brush. No primer. This was done two or three years ago, looks the same today.