I'm thinking either a mirrored 5CP or KOTH map would be best because they're easy to learn, the objective is straightforward, and you can easily say "We won 3/5 matches, gg." instead of "Well you moved the payload to the bomb site in 13:23 minutes, but we had more kills so who won?!"
Either way, yes, we need a couple more sign-ups. If we don't meet the limit we pretty much have to extend the sign-ups for a couple more days.