Felix,
The CSIT command shows the CICS MAXSOCKETS setting.
The CSOCKETS command shows the status of sockets. You can issue SELECT STATUS EQ OPEN to see how many are active, or GRAPH CICS * CICS_SYS_IpSocketsActive (or use short alias CSOCKACT) will show a count.
Metric CICS_SYS_IpSocketsActive% would be percent active of MAXSOCKETS.
It doesn't look like the active and max numbers are shown on a display together, could be submitted as an Idea.