You have two goals when adjusting your WDH. First, restore weight taken off the front axle. When you apply downward force behind the rear axle, upward force is increased on the front axle. I believe your vehicle recommend restoring all weight lost. Many people find using an estimate of relative weight by body height at the front fender good enough for WHDH adjustment. You can adjust the number of links under tension as well as the angle ball. If you cannot get the front to unhitched height, you need stronger bars.
The other goal is to get the trailer level to slightly nose down after WD applied. On flat ground, measure the frame height at the front of trailer and rear.
I recommend reading
this thread and adjusting yourself over taking it to a dealer. Your TW may vary if you plan to fill the back with toys vs. empty so you may need to change frequently.