I just Justin Clamps and Super Clamps regularly. I'd have to see the specific column to give you a specific answer. Gorilla Pod could work if you knew people wouldn't mess with it.
It's on the right edge of the frame in the image in the first post. Too thick for regular clamps to work. Might be able to clamp on one of the scrollwork trim bits, but that would be precarious - also, those might be hollow plaster or paper mache, not sturdy stone.