I found this dinning buffet table for a great deal and am thinking of using it as a double vanity for my master bath. It has a small dent on the back in the left corner towards the back. Any ideas on how to fix that. Or is it best to replace the top with a granite slab? Also, I know I will need to apply polyurethane to protect it from water, but sometimes that leaves bubbles and not a smooth texture. How can I make sure there are no bubbles and keep a smooth texture. How many coats should be a applied and should I apply any coats in the inside?