Well, you could keep the 'lower tiers' of the league (like the first matches) private, people just hold them between eachother. You'd need some 'neutral party' there to make sure there's no cheating. Say if player A won 5-3 against player B but player B wouldn't admit it afterwards.. Or you could opt to do it all in one day. Please do make sure if you do that, it's a timezone everyone is generally AWAKE. As in, if you can please keep the start somewhere between 6 and 9 pm GMT. Or split up the league into two parts so you don't have issues like starting at 10 pm GMT and having the league continue until 1 am GMT (2 or 3 am or later for some of the Euro players) due to the sheer number of players (even 5 duels can easily take 1.5+ hours if the players are competitive).