Something not mentioned yet is the load leveling system does NOT address the same issues as a WD hitch.
Load leveling only affects the ride height of the rear of the truck. It does nothing to help prevent sway events with the trailer, and it does nothing to return weight to the front wheels of the truck.
Hitch up your trailer and watch the front of your truck as you lower the tongue on to the ball. The nose of your truck will go UP. That's weight coming off your front wheels. Maybe it's enough to affect steering and braking, maybe not. 3500 duallys can usually stand to lose some weight off the front without affecting handling, especially if they are diesels.
What the WD hitch will MOSTLY do in this situation, is provide sway control. These WD hitches with integrated sway control are much more effective than the cheesy old friction bars, plus they are ready-to-use. You would need to have friction sway control attachment points welded on to a heavy hitch shank. By the time you are done paying the fabricator, and buying the parts, you're well into a modern WD hitch with integrated sway control.
Plus while you may not "need" to have weight transferred back to the front end of the truck, the truck will definitely handle better with a properly adjusted WD hitch in play.
It may not be necessary, but it is still a good idea nonetheless. I applaud your decision to order a WD hitch.