If you look into the cumulative weight contributed by each part of an airplane the weight difference in adhesive is minuscule in comparison to everything else and yet failed joints are one of the leading causes of airplanes being lost. A better place to look is in tires, fuel tank capacity (do you really need a 20 min flight duration?), battery pack size, etc. Many GeeBee fuselages are designed far heavier than they need to be. The inherent rigidity of such a wide and short shape simply doesn't require a multitude of plywood bulkheads and longerons.

That being said, I use Titebond wood glue for most joints because its cheap, lightweight and handles shock better than brittle CA. I still use 30 min epoxy in high stress areas.