Like all the above have said, but I have found that the term "sway" can mean different things to different people...
Meaning, "sway" to me is a total see-sawing effect of the steering wheel to try to correct when the trailer is totally out of sync with the truck..
I feel wind and I feel semi's and even little eco-box cars go flying by me and what I feel is a "push/pull" effect on the whole rig, but nothing like the see-saw effect of the steering wheel..
I just have a basic EAZ-Lift WD setup that over 18 years old (#1000 bars) and it handles my new Rockwood just as well as it handled my old Prowler.
I felt the same push/pull effects with the smaller, lighter Prowler as I do with the longer, heavier Rockwood..
Nothing to ever even trigger the trucks computers "sway control" on the truck..
Anyway, what was said above you should still do to get the weights right..
I towed my little 8' utility trailer one time and just plopped 3 bags of instant cement in the back of it and drove home about a mile and it swayed once I got over 25 mph! I had to baby that thing home, since it was only a mile and if I had just put those bags over the axles, or in front of them, I could have driven that thing at hwy speeds with no problem....
Good luck, Mitch