Normally, as long as the strips extend beyond the internal stem, you should be fine. Do you plan on adding an external stem? In the One Ocean plans and instructions, I believe he does not talk about external stem being that large or wide to cover the ends of the strips like other plans, but rather have the strips mitered at the ends and interlocked like your picture indicates. If there are gaps, you can add a wider external stem once you plane and sand back to the internal stem and then shape that to your liking.