[Legendary League]

I wouldn't worry about races being imbalanced at all. The main concern of a host is whether or not to allow LA Ermor or Rlyeh (due to their dom-killing dominions) if you're playing LA (I allow it in my games, but others may feel differently in a newbie game). As for cheating and exploits, again I wouldn't worry about it. The game is rather (over)zealous as is about cheating, and there are only a few real cheese to worry about, like exploiting 0 gold Ettins (from the City of Shamblers site), and the really cheesy trick of sending 50 items to a person who just put up forge of the ancients, etc.

Again, hosting is relatively straightforward. The main thing is to watch for stales and make extensions when needed, and to lengthen turns when the game transitions into the mid and late games (generally goes from 24 hrs to 48 hrs, 72 hrs if turns take really long). Also, find subs when people need them.