RE: How to build a balsa sheeted foam core wing.
Having weighed & sorted every sheet, I'm happy to report that the lighter half of the 100 sheets averages 8.7 pounds/cu ft. The distribution of weight is definitely humped to the light side, with a relatively small number of individually heavy sheets tailing out on the top end of the distribution. So I have a small number of sheets that I can use where I need wood strength, and I can get good value out of pretty much the whole pack. So yes, I would do that again.