I looked at a Haul Master bolt on hitch receiver....
It looked well built, but don't these numbers seem kinda light?
I'm wondering if they're measuring the bolt shear strength???
I can't imagine hauling much! It seems like a heavy lawn mower would meet the 500lb tongue weight limit!
I'm still liking my idea of 1/4" plates coming down beside frame rails, and a step horizontal plates welded across width.
I can get 10" & 12" channel in place of the 1/4" steel plates.