Order the WD hitch without the ball.
Call the dealer and get the ball size in the morning. Buy the ball locally after you have received your WD hitch so you also know the correct shank size and length. Some WD hitches take longer length shanks than others.
I'm done. This isn't a place to be helpful. It's a place where curmudgeons with a superiority complex will nit pick everything. If you want help, go elsewhere. Admin, delete my account please.