Stanford Torus vs Bernal Sphere

Hi,

Mike -- in one of your mails you mentioned the following

The published designs for the Stanford Torus and the Bernal Sphere had the same population (10,000; you're aiming higher), so that's a basis for direct comparison. The masses listed in those studies were
10 million tons for a Stanford Torus and less than 4 million tons for a Bernal Sphere. As we scale upward, this ratio might change, but I don't really see it reversing.

This would seem to suggest that a sphere is more efficient of building materials than a torus.

For the structural masses (of the Bernal Sphere and the Stanford Torus)calculated above, what rate of rotation have you considered for both?
Are the masses 4 million tons and 10 million tons both at the same rpm or are they at different rpms, i.e., 1 for the Stanford Torus and 2 for the Bernal Sphere? Basically, I want to know that if we assume 2 rpm to be a safe rate of rotation and construct both the torus and the sphere to rotate at 2 rpm will the Bernal sphere still be more economical?

Thanks and regards
Saatvik Agarwal