I have the same problem. I don't think there is a way to set it to two players. I believe that when they start the server they enter with four players then leave. This unlocks scoring until the server is shutdown.
I found a way to play without scoring which involves using proconrulez to write in chat who killed who and with what weapon( you could also set it to "yell" witch means the kill info will be flashing on the screen of all players). You still won't be awarded points i'm afraid. You can check out
Procon:
https://forum.myrcon.com/showthread.php?5813-Download-Procon-1-XProconrulez:
https://forum.myrcon.com/showthread.php?2958-ProconRulz-V44j1-weapon-limits-and-other-event-triggered-admin-actionsProconrulez guide:
http://www.forsterlewis.com/proconrulz.pdf