I haven't used the hammered paint, but I've used the "Stone Creations" paint quite a bit.
It's nice because it hides flaws, but it requires alot of overpainting.
You start with a base coat, then put on the stone flecks coat, then go over that with several layers of clear.
It works really nice for the coin door panel on cabs though.
I've used it on several CP's as well, but didn't bother to paint the area under the overlay with the stone part.
I was using .010 thick lexan for my overlays, so it covered any imperfections in the wood/paint, underneath them.
If you are planning to use vinyl without a heavy overlaminate, it will show every imperfection in the panel beneath it--especially if the art is not really busy.
I quick covered a couple CP's with black vinyl, just to have something on them, and it showed every dent, every nick, and every spot that the wood filler was "almost" completely flat.
That was thin glossy vinyl though, so it was the reflections that were the main culprit in showing flaws.