Use the 3/4. if you pre-drill with a smaller drill bit before you screw it together you shouldn't have a problem. I am working on a rack and a guy at home depot gave me a great idea. he said every time he uses melamine he drills and then puts some wood glue in the hole then drives the screw in. It will keep it together a little better, as long as you are not planning on ever taking it back apart.