If your towing over 5000lb. more than 25 miles or so, I would seriously use an equalizing hitch, with the 1000# bars, and a sway control...a simple sliding bar/clamp type works very well. Open trailers aren't to bad for sway as long as your load is 10-15% tongue weighted, but a closed trailer can be a nightmare without the proper equipment. Most trailers are built to put 15-20% bias toward the tongue. Notice the axle setback.
I load mine the following way....
#1. Measure tow truck rear bumper height @ normal ride height unloaded....
lets say 22"
#2. Set ball height so trailer is about 1" higher than level (trailer still not hitched up to
tow vehicle)
#3. Hook up trailer, hook up equalizing bars so they are level or slightly pulled up at the
rear of the bar (chain link end).
#4. Load vehicle and all additional items on trailer, so that the rear bumper height --
(Previously 22") is now about 1"-1-1/2" lower than before. Any more than that, and the front axle steering or weight could be affected negatively.
This should put the trailer at an even level, which is essential for equal axle weight distribution, and will keep the tongue weight at the desired 10-20%.
And don't forget to use tiedown straps that are rated (for total of all straps) 4X the weight of the vehicle.