Okay, I'm not going to touch on the stars since I'm still waiting for the translations and I was going to touch on that in another thread.
But friend, reviewing the blog and also the thread where it was accepted, I don't see any evidence of the contextual differences between using it as a dimension or a planet, because as we saw previously in the Hell section, no, it doesn't have infinite size (it uses Mugen, but as I explained, it's more of an expression than referring to a place itself; I mean, you just have to read Denpachi to understand it).
Also, regarding it having a day and night cycle, in the first instance, the novel tells you that the moon is fake; it never had a star surrounding the planet (what was said in volume 0 is a continuity error). That's why using the mention of night (
I say, even Issei hesitates to call it that) is only a change of atmosphere, it doesn't change anything.
The 7 floors don't change anything; it doesn't tell us their size; under this concept, we can't consider it larger than 5-B.