I'm designing drawers to fit beneath my newly constructed workbench. The outside dimensions of the face frame is 54" x 20". I plan to have 3 columns of drawers each with 4 drawers for a total of 12 drawers. I don't want to spend the $$ for drawer glides, so I'm thinking of using hardwood runners on the sides of the drawers. THE QUESTION IS: should the dado go on the side wall of the carcass (with the runner on the side of the drawer), or on the side of the drawer (with the runner on the side of the carcass)? How deep should the dado be? Do I need to worry much about the weight of the tools - can this type of design handle heavy loads?