[Shoulen]

Create a variable for each time, like Team1 and Team2

Code:

new Team1;
new Team2;

And every time you assign a player to a team add 1 to the variable and every time you remove a player from a team, subtract 1 from that specific team

And from there make sure there is in imbalance, so if you only want to let the teams have 2 more players than each other before auto balance commences then do something like

Code:

new check = Team1 + 2;
If(check > Team2) {
// Autobalance
} 
check = Team2 + 2;
else if(check > Team1) {
// Autobalance
}

I hope that works, it's untested.
Bottom line is you need to run checks to compare them as a ratio.

EDIT: If mine doesn't work just follow the above Tutorial....

- Shoulen