Sisty88, I hadn't thought about the issue of the clamps sticking, out, so thanks for mentioning that. Tablecloth clips sound like a good idea.
KenmoreGal2, I'd thought about the pins scratching the table already and was thinking that I'd have to put my large cutting mat under the quilt, but it would be better if I had something bigger. I can get some acrylic at the hardware store, but I'm not sure how big I can get that. This was issue #2 after the clamps, which were the two things that have kept me from doing it on the table.