More after-the-fact advice: if you really want the highest strength-to-weight ratio for a wood boat, you should go with stitch-and-glue over strip-built. The typical 4mm okoume plywood is made of 3 plys with varying grain orientation which provides greater strength than a single ply (or strip.) To some degree it's an apples-to-oranges comparison, since we're comparing harder mahogany to softer cedar, but even if a 4mm stitch-and-glue boat weighed the same as a 1/4" cedar boat and assuming an identical lay-up, I'd wager that the plywood boat would be a good deal stronger. How strong can Elmer's glue be? Dean