>>96387389
Are they layered? I was under the impression that they're just floating around in a void.
>>96409206
You're right about the edges, but they are definitely finite. But yeah GW keeps things pretty vague intentionally when it comes to scale. I think hysh is the only realm with a full map because it's autistically symmetrical.

Here's a "map" of Aqshy with the great parch visible, which we have a detailed map of and we can assume is about asia sized (back of a napkin math). So yeah extrapolate that to the rest of map size, discount maybe the last third because of uninhabitable magic bullshit, and you get the approximate (inhabitable) size of a realm.
In practice though gw just has everything of note take place in each realm's respective mapped out landmass (great parch for aqshy, ymetrica for hysh, etc...)