Hitch ball height with Reese Weight Distribution System

I have been using that system on three trailers since 2004 and the easiest way to adjust the chain length, which determines whether or not there will be contact during sharp turns, is to adjust the ball tilt. That brings the back of the bars up or down. Level or close to it is correct for the bars but cannot always be achieved. How much tilt is mainly a trial and error kind of thing as you are also adjusting transferred weight at the same time. Bars lower in the back are better than lower in the front.