I'm probably in the minority but I believe that the type, thickness, and grain orientation of different woods is a major part of the strength in wood composite construction. I believe that the wood core is at least as important as the layup. Mike Loritz has written some good comments on his theories about different woods and thicknesses. You can probably find more by searching the forum. I have experimented with strip and plywood thicknesses and find that I can increase or decrease the strength of the hull by varying the wood thickness and/or by using different fiberglass layups. It's not just a weight trade off but how you want the hull to perform. 1/4" WRC is basically what you could call a standard. Vertical grain strips are MUCH stronger than flat sawn strips...though for the most part flat sawn strips are used with impunity. We have a lot of flexibility in what we can use and do here. This is good. End grain balsa makes a strong composite core...used any other way and it is not strong. You could get almost the same effect by using styrofoam sheets. Light...but not strong. As mentioned...you probably should experiment....and then post the results for all of us to see.