The more washers you putin the hitch makes the bars point .ore towards the ground thus increasing the weight distributing of the hitch.
Did you buy the 2 parts sway equalizer or 4 pt. The link you provided is for 2 part. I have a 2012 ram 1500 and a larger trailer like yourself and found that you're going to want lots of sway control. I would try and get the 4 pt from the dealer since it helps with sway much more.
I would look into adding more washers or moving l brackets up and trying to raise the rear of the truck a little more. When setting up my hitch which took many tries I was very easily able to tell when it didn't feel right. Once you think you getting close have it weighed so you k ow everything is right.
I found that driving on the highway with other trucks creates much more sway. Driving side streets was easy its the trucks that are going to push you all over the road.
