I am installing a new shower and am looking for advice. Using a Kohler CI shower base and intend on utilizing solid surface material (corian) for the walls in lieu of tile. Question is, I will be installing permabase backer board for the bottom 3 feet than drywall for the remainder. Also, the corian installer is asking to install the permabase backwards due to the slick side normally used in tile install. Any comments or cautions on this install??