I bought 2 cans.... a light and a dark can. I would do light sprays after the first coat. You can also do sprays at an angle after the first few layers dry... this will give you some excellent effects.
I'm just using ceramic on the bottom level and slate on the second. I used Stone Spray to get the effect you see. I also put a very thin coat of matte sealant for cleaning purposes. The finish still has a good traction and it doesn't flake.