I've used both the Elmers Ultimate and Gorilla glue. I liked the elmers better b.c it is a little thinner and spreads easier. I can vouch for the stregth too as I was just shot down and there was no balsa that was not still attached to foam. Once you can tell the wood is damp with glue, just keep scraping it off (or around to a dry area) as thin as you can. The nice thing about this glue is that it keeps expanding and the longer you wait the more glue you can scrape off. Just try to spend roughly the same amount of time on each wing so the amount of glue you use is consistant. I also just got another 16oz bottle to start my sheeting with on my new project.

John