Hitch should be slightly above trailer axle, and tongue weight should be at least 10% of gross weight. You need to carefully tweak these 2 adjustments until you can tow at all speeds with no trailer sway
Agree with Tash. There is no guarantee that the spindle-hitch ball horizontal alignment will result in a level trailer frame. Level the trailer on a flat surface (like a parking lot). Measure from the ground to the top of the coupler. Install a hitch receiver and ball that results in the same measurement. Allow about an inch or two for spring sag on the tow vehicle. Couple up and see where its at. Adjust for level trailer as required.
If truck squats you've got too much weight on it and need to reduce tongue weight or get a weight distribution hitch..... or your not using the right size tow vehicle.
But all the geometry and what not are based on everything being level.
