Resorcinol's rap is that of being harder to work with than epoxy. You can be sloppier with epoxy. Garden variety epoxies may have some trouble with UV and high temperatures but are tested as being stronger than resorcinol. And there are epoxies that perform well at higher temperatures. What are they making the new Boeing 787 from?

I agree that the best strong back is a band-sawed piece of solid white oak. Preferably from an old gnarly hanging tree.

Ben