The teams of three then played as units of one in the 5 person doubles formulas. This allowed the coaches to observe the players that won on a regular basis. The players played the 5 person formula and then rotated the setters. This system also had the side benefit of teaching all the players the systems of service reception and defense. The 12 person system on two courts works very well if you have the 4 players that are out act as ball people and have balls ready in the service area at all times.
Coaches can decide on various scoring systems depending on the time available.
The best system is to use a no limit 15 point game, win by 2, but this does take time. Playing to 11 points or 10 minutes can be a good system or 15 points and 15 minutes can also be used. When using a timed system it is important to break ties by one point With 16 on 4 courts we have used 7 point or 7 minutes. This is only for safety. If no one is playing beside you, then it makes no difference.