Technically, you don't need any cove only or bead only strips. But having a few can make your life easier. The strips at the sheer joint can be cove only or bead only. It depends on whether you are stripping cove up or bead up. If you include a contrasting design in your boat, that may dicatate custom cut strips. Now would also be the time to mill a few narrower cove & bead strips for the smaller radius curves on the boat.