IAS + SQL Logging rights

I setup IAS to log to SQL and created a database with the necesary fields and the report_event stored procedure.

IAS is authenticating as a SQL user I created just for this purpose, it's only permissions on the database are Connect, Insert and has Execute on the Stored Procedures. This works ok.

I tested the connection and it passed.

What permissions should this user have on the DB and stored procedure?

I figured maybe:
Insert, Execute, and maybe Authenticate on the DB and only Execute on the SP?

Also what is the max concurrent connections setting? It defaults to 2 is this ok?

Cheers,