Now this will get interesting
All depends on the intended experience to provide for the player. So far, we can assume INovae want to make a long time frame (24h around ?) in which anyone can still hop in / out at any time.
In that regard, I agree with @Lomsor that restricting capital ships (CS) is not a great idea : the first dozen of hours will see no CS at all if this is implemented. And anyway, there is a "solo play", right? Players should be able to test beforehand how a CS feels in piloting. At the worst, you may restrict a CS on "play X minutes in solo with a capital ship", but nothing more in my opinion.
Other interesting points to ask: how is the money gained? Through escorting haulers to safety / blowing up objectives is my first guess, but maybe other forms? Is there a "regular" income independant of any other objective? Do you, INovae, intend to regulate a snowballing team?
This also could be interesting as a statistic: how much did a player contribute to the team effort