I have a TT with a 2" ball, and a cargo trailer (used daily for work) with a 2 5/16" ball. I wouldn't want to buy 2 of these hitches, when I can only use 1 at a time! I wrote to Andersen and inquired about this situation. They replied that this WD hitch ships with either size ball (yes, 2" is available). If I want an extra ball in the other size, it's about $50 additional. They did caution that the tapered ball can wedge so tightly in the sway-control housing that it may take a press to get it out. Another option they gave was to buy an extra housing with ball for about $200.
I don't have a press, but on the other hand, my tongue weights are only around 350-400 lbs, so maybe a big hammer would do. :)