Gaucho, I typically use a 22 by 22 inch red bandana. Not really sure if it is actually big enough but seems plenty big to me. 22 inches is about 60 cm so I think you're right on. Have you tried something like cutting your own cloth (maybe an old shirt or tablecloth or similar item) to the size you think would be big enough? I have done this with paper to compare sizes of pouches that I could not actually see before ordering on the internet. If you don't want to cut the cloth, simply folding it to the size you want to test and pinning it in place might work.

Philip you left out a use. Using the bandana to cover the shiny spots on your head.