Wait, wait, listen, please. I know, I know, this seems like another port of the same map, and yes, I agree that "DUST2" works as some cheap head-turner, but I would like you to consider this before moving on.
Look at the screenshots,
now back to me,
now back to the screenshots,
now back to me,
now look at this:
Difficulty
Map's geometry gives a serious advantage to human players, so I would advise playing with "hard" bots and putting the "balance" slider at least a little bit in the opponent's favour.
Bot quantity
20 and higher. 5v5 might feel a bit too lacklustre from combat pacing's point of view.
Game length
Up to you.
Modes
Any? I guess? My favourites are skirmish and domination.