What a fascinating premise. Kudos to the author for doing such a thoughtful analysis. His technique for arriving at the cross-sectional shape is especially interesting. I would have never considered that the optimal cross-sectional shape to have been anything other than a circle.

I wonder if it would be possible to orbit the ring in the axial plane, around a single arm of the torus? Or even in a lemniscate, intersecting the inner Lagrange point?