Huh. I just learned that Death Star Owner’s Technical Manual, published in 2013, appears to contain schematics of the Death Star from back when the dish was intended to be equatorial, and has an in-universe explanation for why it’s all different from the real thing.

“Imperial Schematic Design System Data, obtained by a rebel agent from a military communications complex on Galvoni III after the Battle of Yavin, yielded schematics for a concept ‘Death Star’ with a superlaser cannon located on the sphere’s equator.”