It's probably been 2 decades since I've held one of these posters in my hands and my recollection is that they are no larger than 11x17 and made from heavier paper than the football poster. Hence the thoughtful suggestion to not bend it but rather slide it into an envelope.
That game just made me physically ill. Embarrassing. Completely embarrassed. I'll still be at the Maryland game rooting my heart out, but wow, it's freaking bruised.