The documentation implies that of the X and Y axis, the X-axis be longer than the Y-axis. Is that correct? Should the longer axis be the lower level one? And the shorter Y axis be the upper tube? When positioning the footers, should the screws be on the outside (with the pointy trapezoid end facing each other) along the longer axis? Then the higher/raised tube would run parallel to the 4 screw holes on the outside. There are pictures on the web site with builds showing footers both ways, but those are all square builds, not rectangular. It seems like you would want the longer axis lower to reduce sway or movement. Hopefully, I am describing this clear enough. Thank you for any advice.
Nope. Each axis is determined by your needs, one is not longer than the other. A square build would have equal length tubes.
The longer axis orientation does not matter. The legs are equal length either way.
I think I fully understand what you are asking, I think you are just over thinking it a bit. Either orientation yields the same results, the only thing that changes is the direction your spindle faces.
As for the feet, it is the same thing. The load on this machine is not in the same direction as a tube or anything. It is dependent on use and direction of movement. If I felt strongly about one way over the other I would let you know.