I dont think its even possible to have the slots above 4 for coop, so yeah it would have to be versus. Thats weird, so gameservers has the slots at 12 for purchasing a 8 slot server? Thats kinda cool I guess. Ive heard alot of bad things about gameservers.com so, id never use them but hey.
Later I am going to put one of our servers at 14 slots for versus mode and see it actually has 14 slots. Then I will know. 14 for versus sounds fun though. Better than 8 anyways.