I wish you guys luck with all those balsa stringers. Carbon tubing might have helped keep wood stringer breaks to minimum and helped remove some of the structure

Don't know the weight of solarspan. Sounds like it has the adhesive built in.

Polyspan lite adhered with balsalock might be lighter. Balsalock is water based and can be sprayed or brushed. I also have some other great water based spray on adhesives that are heat activated when dry. Contact me direct....

Many Free-flighters do what Dean suggested, 2 layers silkspan. Some free-flighters change the technique and apply lite polyspan first and then come over the top with coloerd tissue such as Plyspan Esaki. Builds into a very light but stiff-strong structure that is puncture resistant. Polyspan must be preshrunk with heat before the esaki. Look in any Free-Flight websites for supplies