I was thinking more like 7 = 1 baddie vs 5 goodies vs 1 indy, hosted 2 Mafias the same size recently so I'm pretty sure I can balance it in a classical setting. If no one signs up till Friday night, I'll trim it, send out the roles and N1 can end Monday.
The individual wincons can't be balanced for a trimmed version unfortunately. Anyone leaving the game would make it lopsided and I don't see enough ideas of individual wincons to make a miracle in-game balance for events. But I guess I can run it again in the future as a redux of the OP if there are more people interested during the summers for example. So, all is not lost.
I'd rather have you play since you all showed up and signed up