Why not go all the way to 30?
I'm already in, but it would give everyone more potential opponents on any given night.
I have never done a league like this before, but perhaps there is an option to boot someone if they sign up but never play any games. You might be able to start with 30 and end up with 15 or 20 after some people drop out (or get booted).
Just a thought - I will now sit quietly and await my 14th draft pick.
Edit: I also bet that with a day or two longer, the thing would be filled.