I like your way of thinking (math!) but I don’t get your conclusion. Yeah, if you have a 6mm circumference, the diameter would be 6/3.14 around 2mm, but a diameter of 2mm is still kind of small… Even if we are talking about a 6mm radius, it’s still small. I guess a size of a pee hole (sorry for being explicit) of 6mm would buy you something big, but other than that, I don’t know.