Black Market limit for demo crews before purchase was 9x. After purchasing the one for balls the limit for gems dropped to 8. However, this did not occur for shotfirers. Gems was 24 before purchase with event items and still at 24 after.
Reporting as bug due to inconsistency, but not sure if is actually deliberate or not. Is this how it is supposed to work?
In my case, I had bought all of them, and with the event, the remaining buffs went from 0 to 1, for each buff...
In my case, I destroyed my last 2 mountains with 1 demo crew from the Joyouse bundle and 1 purchased for balls and yet the game will still allow me to purchase 1 for gems. So there is a bug in there somewhere. Hope I never stumble-click on that puppy.