My theory was that with 2 boats you will want 2 sets, and they do take considerable room on a trailer, might as well make use of it.

A removable external upright would solve any issues with the tracks not handling the load, but that sounds like a bandaid to me.

If you could sneak the upright of the front stand between the hull of the lower boat and to the outside of the trax tire, I bet it would survive.