If your insignia was constructed exactly as the original, then I would orient it in the same manner shown in the ship's drawings as seen here:
PEARSON 28 (1977-80) sailboat specifications and details on sailboatdata.com
This seems to indicate that the insignia has a slant to it, and that it is best oriented along the leech and not the foot.
Edit: Wait, that may not be totally correct. The flagstaff is somewhat oriented along the leech but the numbers appear squared against the foot. Take a look at the photo and you'll see what I mean.