To add to the above regarding PVA glue. Apparently they’re not generally suitable for guitar building as they have a tendency to creep over time. Not ideal on a wingspar, at a guess. Melv, comments?

I don’t know much about guitars, but I have been told by a cellist friend that the glue on a string instrument like a violin or cello is always weaker than the wood (think Stradivarius or Guarneri) so that if anything breaks, it is the glue joint, not the wood.

Harald