Convergence settings of gunners effects only the gun sight settings of the single gunning position.
Usually you set them to maximum 600yards.
But for normal attackers (not the moron who creep up your six) you have to take a lot of lead, so the convergence setting is not real important.
You must be aware of the force, Young Yedi.
The convergence of the whole formation can't be altered.
At least not the normal mortal.
Maybe Hitech will attach a dot command some day.
But the 1k convergence works fine.