The work involves dealing with the camber and toe-in of of the axle, not every welder is good enough . Too much heat and you have bent axle. Too little and it falls off.
I changed my axles to 5200# from 3500#( one had bent) and they came from the factory as an under slung, so I got an unintended axle flip. Adding a leaf to the spring pack, 16" wheels and HD 10ply truck tires gave me 7 1/2" lift. This raised the centre of gravity giving me big time sway, not the tail wagging , but the side ways rocking. I cured that with a single 48"x16"x1" anti sway bar on the trailer and a 1 3/8" on the truck.
I never heard of anyone putting an anti-sway bar on a trailer, in fact the manufacturer's engineer said don't do it, so you're on your own.It worked great. I tested it to the speed limit of 120 kmph (77)on badly rutted pavement with nary a worry.
The added benefit was much bigger brakes.
adventure before dementia