you know, we realized one idea for entry tags that could be expanded...

instead of just:
Closed | Open (jump in) | Open (CS)
we'd suggest this:
Closed | Open (jump in) | Open (CS) | Open (3 slots) | Open (2 slots) | Open (1 slot)
While one could possibly have more slot count things, it goes to say that if there's more than 1/2/3 slots open, you simply use the Open one. and as a bonus, the jump in mode can also use those slot counters if they make sense.

oh, one more that could be added:
Closed (request) - Its closed, but GM is willing to add character slots if your CS idea is good.