Spreading one's team evenly throughout the field gives the team no particular advantage. This is likely to lead to a "fifty-fifty," in which case both teams find themselves stationary, firing repeatedly at the also stationary enemy. Fifty-fifty situations are not only inefficient, but rather boring for both sides.
Instead, find some sort of advantage in either your team, or your surroundings. Maybe your team includes many heavily-armed individuals with automatic weapons. This will make for a nice strong side, or perhaps a long-distance defense. Look for thick, heavy cover. This might influence a team captain to lead his team through one side of the field instead of the other. This will give the captain's team a strategic advantage.
Whatever the case, finding a strength and acting on it is a proven strategy. Splitting a team up into "thirds" will only give the opposition a obstacle spread thin.
