Most of us use the tongue jack to assist with getting the WD bars in place. My Reese came with a pipe/cheater bar that absolutely needs to be used on the "snap-up" brackets. They "snap" because there is tension, a lot of it.
Reese recommend 5 links under tension minimum, no max. I have always run 6-7 under tension. You can adjust the angle of the hitch head as well as links under tension to accomplish the desired WD. More angled down/toward rear and fewer links under tension increases WD to TV front axle.
Consult Barney's thread as well as the how a WDH works by Ron Gratz.