You're gonna have to pick a specific depiction of Aincrad though.
Light Novel depiction of Aincrad is completely different than the Anime version. And the Anime version in general is inconsistent with the Ordinal Scale version based on Floor 100 depiction.
And then there is the problem of "Where do you pick as Floor 1" when the outer depiction has all its outer walls closed. As such, I would recommend against doing the pixel thing, with such inconsistencies muddling the scene. All we know for sure is "The Floor above is smaller than the one below".
I would recommend just picking Floor 1 size and acting as if it's a circular pyramid for calculation, featuring 99 Floors with a height of ~100 meters, as Floor 100 has no ceiling. v8 may have additional info about the basement dungeon, but I'm too lazy to check.
I have no idea where Leaf got the "100 kilometers" from for Floor 1, but it is 10 kilometers in diameter. Quite the drastic difference.