I played in a 2v2 tournament. It was very interesting. To ensure the tournament took place, the organizer set a fixed time for the game. If one of the teams didn't show up, they would forfeit. Once, I was late, and Lebron had to play 1v2, but he managed to win :)
According to some, the best mode is Warlord Tactics (WT). A script for manually adjusting alliances solves the problem.
I remember playing with Lebron in a 2v2 tournament when he was still a newbie in Heroes - it was great to play and share experience.
Therefore, I would suggest pairing up: one experienced player and one beginner.
Regarding the time limit, don't listen to Rebellius - 4 minutes is crazy. :smile11:
It should be 2 minutes, although I prefer 1 minute - but at that speed, few people can move the mouse quickly enough.