Read the sticky at the top of this section on getting cat scale weight. You must make 3 passes to get all the info you need:
Pass 1, just the truck with the gear and people you normally tow with.
Pass 2, truck and trailer without WD bars attached but with trailer loaded as you will tow.
Pass 3, truck and trailer with WD bars hooked up. Only then will you know what your weights are and how much you are distributing to the front of the truck and back to the trailer.
The trailer also should be level front to back when hooked up on flat ground. Slightly nose down is ok but only slightly. Nose up is not recommended.
