My Blue Ox WD hitch instruction say the trailer and tow vehicle should ride level.
My TT is 24" corners to ground when it sits level unhitched. So I adjust the WD hitch so it is about that on when connected to the truck. An inch or so does not seem to make much difference so I keep the nose lower.
Empty from the dealer I was on the 7th chain link, he said I would have to check when loaded for the road. Loaded for the road takes 8 or 9 links.
So to the truck, then ready to go the wheel wells are about and inch or so from their non-loaded position. The proof of course is in the ride I really do not notice the difference of one link.
If the TT and TV are not aligned, the tension on the bars is not equal. I notice this when parking at the campsite, as I rarely get a completely straight shot when backing in.
To hitch or unhitch I use the tongue jack to lift the ball a few inches to reduce the tension on the bars.
The scales say I have about 12% on the hitch when loaded for the road, depending on how heavy we load the TT.
You can do a lot of tail chasing trying to get the perfect match, but the weight distribution usually changes during your travels anyway.