[Anthony]

It's debatable whether a ring configuration makes sense. The general virtue of a ring type configuration is that the atmospheric pressure can be supported the inside of the ring rather than along the entire radius of the spin compartment, reducing the amount of mass you need for atmospheric containment, but this effect is reduced if there is a pressure difference between top and bottom of the chamber.

Judging from the diagram, the outer torus has a height of around 150 km. At 0.2G and 20C, the scale height of the atmosphere is roughly 40 km, so the pressure at the top is 2-3% of the pressure at the base, and you're barely saving anything.

A cylinder with length 650 km and radius 250 km (i.e. just reversing the dimensions) has the same projected area but lower structural mass. It would rotate a bit faster (period about 26m instead of 42m) but has lower velocity, and is probably simpler to construct.