Poly glues do not stand up well to heat, Gorilla included.... West Systems Epoxy should provide the bond you need.......PVA's handle heat better, if proper machining is done. Also if you use a "mortice/tenon" type joint you will increase the surface area of the glue joint. All exterior panels we use for doors have at the very least a .625 rabbeted joint...even better is using a glue joint cutter which will increase the bonding surface by at least 4 times. No reason to leave material clamped for 2 days...after 1 hr most bonding agents for wood have achieved their strength...what you need to wait for is the wood at the bond area to return to it's original MC. Search the woodweb adhesives forum for more info on glues and the proper bonding of wood substrates.
Gene Crain
www.plantasymaderas.com