All of it. No, seriously. Get a big group of people and run one ship per person, limit one upgrade. You pick the upgrade, so nothing ridiculous (like Soontir Fel w/
PTL) comes into play. Each person will be able to focus on getting the hang of one ship, but use teamwork, and everyone can get involved. I'm speaking from experience,
btw. It was a huge hit in a game club I joined. As was a 9 person zombicide game, but that story is for another thread.