Rod Wise

will be building geebee z from wendell plans and others plans.say to use wood size from 29% to build 40%what do people think about that and how would you find out the answer. look at plans for planes of simuler size weight its 112 inch span 23lb as 29% 40lb as 40% big diferance don't see how wood size for 29% works for 40% any help would be great thanks