Hi Joe,
Yes, 10 minutes works OK as this is less than the default 10 hours of clientSessionTimeout.
The two timeouts gives different disconnect messaged though. The sessionTimeout clearly states that the session has timed out, the clientSessionTimeout gives you "[wsnm_xmlapi] sessionId=0 detected as idle" and some generic disconnect messages.
On the thin client it states "You have been disconnected because you logged in from another location, you logged off or your host was shutdown or restarted". Not that helpfull message..
So for me the solution was another registry key.