It doesn't really matter how far they run from the boat, especially if your running worms. After a few minutes if your doing things right all your boards should be pretty close to the same ft back. How many times have you gotten bit before the board is even clipped on? The spread in ft bk is only used to pinpoint the most active biters, a certain ft bk will most likely dominate the others and one by one you will eliminate the ones not producing. But if you troll up wind more line out will reduce boards jumping in choppy water.