Travel trailer sway

Following the directions that came with load bars it says that I should have no more than 1/2" difference between front wheel and rear wheel measurement after instillation. So I get that it's gonna sag. I just never figured how difficult this would be on a truck designed to haul twice as muh as my original tow vehicle. I'm also starting to wonder about the trucks leaf springs. At 750 lb tonge weight I don't think it should sag 5".... I'm going to go through the set up again tomorrow measuring all 4 wheels and adjusting as needed.. I have 2 links I can use right now and I would like to have more adjustability..