I love these disingenuous threads. To answer the OP: 7.
Seriously, there's a team league running in NYC now and regular tourneys going on all the time. Modern Pinball just had a series of enter-when-you-want tourneys, there was some weekly pingolf at Reciprocal before the team league started up, etc.
It all depends on how you advertise. But there are tons of people playing competitive pinball in the NYC area, as you well know. Easy opportunity for large turnouts if you advertise.
And the Creek & Cave pins need to be fixed, esp. now that league has started. You should remind you-know-who.