The Weigh Safe Ball Mount system will only give you "static weight". It is not adaptable to any weight distribution system, so the "best you can expect" is to install this scale on your receiver, hitch the trailer, get your total "static" tongue load, then unhitch, install your WD hitch, rehitch and apply your WD bars. You won't be able to get any weights with the WD hitch on the rig, so all you'll know is how much the trailer tongue weighs "sitting on site, ready to connect to the tow vehicle.
Some may find it "reassuring" most will find it is very limited in functional use, sort of like having a 100 piece puzzle with 10 pieces missing.... YMMV.
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS