After the hull is stripped I do use a sharp block plane to knock down the edges. The plane has to be sharp and you need to have had some experience with such a plane or you may end up with some gouges you didn't plan on having...and maybe even then. A good alternative is to use the ROS with 50 or 60 grit for all the fairing. In answer to your question...no I don't get any large gaps. Even though the inside of the hull MAY not be as tight as the outside it's still gonna be pretty tight. In actuallity even the inside would probably be adequately tight enough for all but the finer quality (and very much more expensive) boats. John's planing jig is a good way to go.