how mutch w/weight distribution?

You should adjust the bars so the same amount of weight that was taken off when the tongue is placed on the ball is restored back to the front axle. That amount will depend on the weight of the trailers tongue and the distance from the rear axle to the ball. Some manufacturers suggest returning only a portion of the weight instead of all of it. I am of the opinion that all of it should go back on the front.
Barney