I'm getting ready to make some drawers with dovetail joints for the first time. The sides and back will 1/2" ply and the front 3/4" ply. I have a 1/2" diameter dovetail bit but it would seem that would be too large to use for 1/2" ply. Is my thinking correct? Do I need to use a 1/4" or 3/8" bit? Thanks.