To find out what stairs you can currently challenge someone in, first go to the Main Stairs Page, then click on "Show your stairs only" link. The ones in BOLD are ones you can make a challenge in. .
Vikings: Brainking should be able to check each player/step to see if there are people for them to play. Maybe an automated message could be sent to them. If they do not play anyone after a certain time of being available then, either removed from the stairs or dropped a place. It could all be done automatically after Fencer writes the code