I have been trying to find someone who has printed their chalkboard style invites at Staples/Vistaprint/Mpix. I would like to see a sample of what they turned out like. Also, is it worth it to upgrade to the 100 lb. card stock or will 80 lb. be acceptable? We are having a very casual backyard ceremony and reception and it's far from satisfying all wedding etiquette guidelines (hah!). Thanks in advance!