I am having a lot of trouble with the shiny tiles getting the image to stay. I have used Stazon, then colored with Sharpie pens and then sprayed with a sealant. When I spray, the Stazon and Sharpie ink runs all over the place. What am I doing wrong? Am I using the wrong kind of tile. I have been using the shiny tiles and not the tumbled tiles that everyone is talking about. I can't find any pretty tumbled tiles at the store. Thanks!