the conventional wisdom i was taught was that use epoxy in high strength areas like joining wings and installing vertical and horizontal stabs. having said that I have read from plenty of forum members about using wood glue for the stabs. frankly from what i have learned about glues from my woodworking is that wood glue is sufficient for alot of areas and epoxy good for adhering dissimilar materials. I have glued table tops together with nothing but a butt joint and some wood glue, and if you make sure to use a planer or jointer to smooth the joint its a sufficiently strong bond. I would personally have confidence in using wood glue on the stabs because its basically a [link=http://en.wikipedia.org/wiki/Dado_(joinery)]Dado[/link] joint. i have the problem though that i don't have the confidence sometimes and fall back to the conventional wisdom. sure the epoxy is a strong bond but i have my doubts its any stronger than wood glue in the situation. for firewalls and such you are really joining dissimilar materials, ply to balsa, which result in weaker joints. You will get all kinds of different answers on this subject.

On the subject of white elmers glue to yellow glue. its bit confusing because some yellow glues that are advertised as wood glues are Aliphatic resins and some are PVA's. I use titebond for building airplanes as well as woodworking projects. which is an Aliphatic resin but titebond II and III are PVA the waterproof titebond being something different all together. the elmers yellow wood glue is a PVA as well.