I have not liked the way the gray water tank is supported on our 2015 13 standard Scamp. Pipe strapping and sheetrock screws!! There was a post on this site last year about a gray water tank that had fallen off! Added to that is the fact that underside on our Scamp is very rusty for being only a year old. I have had to repaint much of it. So: I  made up four eye bolts from 1/4" round stock and two supports out of 1/8" X 1" aluminum angle stock. I did have to drill two holes in the riser to the table area but I used SS bolts and fender washers so it does not look bad. I also used bicycle inner tube between the aluminum and the tank. The eye bolts have a nut on both the top and bottom of the aluminum. I think this is a big improvement over the original method of supporting the gray water tank.