According to what I've seen one just types "set watch=(<number> <name> <port>)"
where number is the frequency with which one would like to check logins, name is the username of the person you're tracking (though it supposedly can be set to "any") and port is, for example, tty0.
My eternal gratitude to anyone who can give me some good advice.
Alex
-- It has long been known that birds will occasionally build nests in the manes of horses. The only known solution to this problem is to sprinkle baker's yeast in the mane, for, as we all know, yeast is yeast and nest is nest, and never the mane shall tweet.