@jwaya - Thanks for your inquiries! I applied Mod Podge matte finish to the foam core board directly then laid the trimmed charts on top, smoothed out with a ruler/straight edge. Apply outdoor in warm weather 65+ degrees or in a well ventilated interior area. It has a definitive odor until it thoroughly dries. Once dry, I applied a coat or two on top, as well. This made them easy to keep clean over the years.

(Aleene's Tacky Glue is a bit less expensive, less odor and would also work well, however I would not use hot glue). I've had a better success rate with durability, in particular, by using Mod Podge for my projects.

Measure and Trim the charts prior to applying onto the boards and I'd approximate that I was able to keep about 70% of the original chart due to size of boards available.

Amazon may be able to assist you in finding larger sizes of foam core for your needs.

Hang onto wall by either tacking a finishing nail into the corners (which end up being nearly invisible) or glue some pop tops onto the back as hangers! Most of all, have fun! - Marie http://www.SacredHomeSpaces.com