I am wondering what type of SQL query would show concurrent calls (Max) or similar for the system as a whole and/or parts. I am not sure where to find this in the DB. Any ideas of this or anything similar that you might be using? Thanks in advance,

Have you looked at the (Graph) Erlang Study report? If you have your lines and line groups configured correctly for reporting, I think that may show you what you are looking for (if you understand Erlangs). Also the other (Graph) reports in the Lines section, for Outbound and Inbound.