Yes, it will be in the docs when they get updated for 5.0, which will be right before release.
Essentially you can have as complex of an interior as long as it doesn’t show up pink in Lumen Surface Cache viewmode. And even then, if it’s a small area then it’s no big deal. The pink areas just mean that Lumen will never bounce any light from there (and it will be black in reflections).
Something like this works:
But a complex mesh like this has pink areas, even after cranking up Max Lumen Mesh Cards (new setting on the mesh)
In the Star Destroyer, getting perfect Surface Cache coverage isn’t going to matter much, since you’re outside of it (you don’t rely on the GI bounce from it much), and Screen Traces are likely handling most of the GI anyway with such small scale features.