Any craft shop gun will do. Only glue to the chines and the inside of the keel where your fiberglass tape is as the glue can pull the veneer off of 3mm ply. If you heat the glue to get it off it will be sticky so gently chip it off cold  and you'll be fine. SEEYA Jack

I did a SW Sport hybrid, and at this stage of the build the hull ply was already epoxied, so no worries about ripping the ply. This meant I could hot glue them in fairly generously, which stops them moving about later on.

It comes off fairly easily by peeling or a sharp chisel. 

My glue gun had a choice of low melt, which wasn't really strong enough, or a more general purpose hotter melt, which was good. Most guns will come with a selection of nozzles - a long one is useful for the forms near the bow and stern.

Good info- thanks guys.

Hickory

When I started, I was using craft hot glue.  It didn't work.  I switched to hot glue specifically for wood projects and it was much stronger!