Hi Kristopher,

The polyurethane glue will work it has a long clamp time and requires the presence of moisture to work. I prefer to keep the panels as dry as possible.

Most wood glues are stronger than the wood and will work. Water resistance is not mandatory because everything will [should] be encapsulated in epoxy when you are done.

I use DURAL Marine glue for much of my work on kayaks and paddles. It is a "plastic resin" in a powder form that has to be mixed with water. It has a long working time, is strong and waterproof.

Hope this helps.

Hank