I'm in the process of recoloring Shun-Pop's Star Wars AT-AT model and I'm planning on enlarging the pieces considerably. I won't have a problem in printing them, as I have access to a 36" wide inkjet plotter (HP 1050C). I have a friend that works at the local Kinko's who will be dry-mounting the four 31"x42" sheet (enlarged around 350% from original) to stock. My question is...what thickness of stock should I use? I don't know what to tell my friend when I bring the sheets up to him. Of course, I'm not exactly sure of what thickness of stock he has available. Does anyone have a general idea on what stock I should try to use?