Trailer towing hookup questions

Trailer should sit level, and 10% of the loaded trailers weight should be your tongue weight.
I've used the U-Haul trailers a few times with the ratcheting net that goes over the front wheels, with safety chains. That has towed fantastic.
I have also added cris-crossed ratchet straps to prevent side to side bouncing, though it was probably unnecessary.
Car towing was either local/short-haul or long distance behind a moving truck, so I didn't worry too much about tongue weight. My camper is lightweight, so I estimate tongue weight by feel, so not too much help in that department.
Link below to measure rise or drop. I measured my truck with the weight of the trailer on The hitch, but measured the trailer while it is sitting level on the tongue jack.
http://www.cequentconsumerproducts.com/_literature_104079/How_to_Measure_Ball_Mounts