Been there, done that. I liked it better in the taller configuration. You can swap ends and put the short side into the hitch and the long side up. Doing this allows you to mount the canoe upside down with the bow on the truck roof, and the stern on the extender. It worked, but, there is too much "slop" in the system. It will sway back and forth over and inch... even when you strap down the top on an X pattern yo the bumper it still moved too much for my liking.
Jason