You're currently looking at the vanity, you don't have it yet? Does this vanity come with the countertop, or you're ordering a countertop for it? If you're ordering the theophylline, ask them to cut it to 63", the put your block on the sides of the vanity to cover the holes. The do your backsplash on the walls, then caulk where the countertop meets the backsplash.