The deal is that no one really knows.....layerable of even the most "layerable" products, like Zaino, is still under debate. The only product where someone tried something is Klasse SG. I can't remember who it was, but someone put some SG on some plastic wrap and then let it dry to see a "scale" of some sort on the film. It would be great for someone to see if they can layer it in this way, and measure the film build.