This was the original one, but it is outdated since it came before the Kaioshin realm was introduced.
This was the updated one, also used by the anime. The anime map is identical, so any one can be used.
Btw, if you ask me, Earth is at the edge of the universe, so the observable universe sphere should also be placed somewhere near the edge, which would inflate the result by a lot, if we decide to go that route, but it certainly can be discussed. We can probably make two ends for the calc, one assuming that the observable universe fits at the bottom center, and the other assuming that the observable universe fits somewhere near the edge.