I think it's relative to your servo power and size of plane. No on just Balsa sticks, but a 1/4 x1/4 Balsa stick with a strip of lite ply on top is fine as well as a small stick of bass wood. A standard servo on a trainer type plane does not put out alot of force on the wood. A larger model with 100+oz servos needs another application.
As far as glue-all will work but once again high power heavy servo applications may require epoxy and screws or pinned applications where lite loaded servos need med to thick CA.