20 min games are too disruptive, insufficient time to establish tempo and build understanding.
If you MUST try it out over 1 or 2 games, 40 min games would be better. To 5.40pm: A vs B To 6.20pm: B vs C To 7.00pm: A vs C
Tiredness should not be an issue as the regular 6pm game sometimes stretches past the hour. In any case, there is the option of being goalie. Or they can indicate their preference to be in team A, so that they can take a 40 min breather.
Also, for those who can't stay 2 hours and need to leave early, they can be in team B. Likewise, those who are habitually late will not be in teams A or B. ;D
And for those who need time to settle down and establish rhythm, they can be in teams B or C. Something for everyone. ;D
Still only 8 votes. I'll give it another week. If my suggestion of playing with 3 teams over 2 hours isn't vetoed by the time I put up the schedule thread for the game on Saturday, 18 May 2013, I will try it for that game.
The players who are opposed are at liberty to canvass votes against over the next two Saturday games.