I think that if people show up, they won't be turned away. It should be a minimum of a running toyota, but if some people trailer the paseo/tercel, whatever. Everything started somewhere. 12 people don't really have the luxury of being selective do they?
I would encourage the 12 whom have committed to the meet to find someone else to bring with. and so on, and so on. I hoping for at least 50 to show.