Best way to create and position ceilings?


After following advice received here, I’ve managed to create walls and floors that are more-or-less properly UV mapped, as well as created them in a way that eliminates light leaking from the corners. However, with ceilings, I’m not sure which is the best way to go about it. Part of what I learned is to not have the walls, floors, and ceilings extend beyond each other because that’ll cause shadow bleeding issues, but if I follow that guideline, it also makes light leak in from the corner of the ceiling. Here are examples:

This is the ceiling encompassing the top of the room without extending beyond the walls; and this is the result.

This is the ceiling encompassing the entire top of the building, and this is the result.

As you can see from the last picture, in the corners there are deep dark spots that occur when the ceiling extends past the walls. So how should I make my ceilings if on one hand, it leaks light because the ceiling doesn’t extend past the walls, and the other hand it causes shadow bleeding because it extends past the wall? And if it makes a difference, the top of my walls do have faces that could possibly be causing the shadow issues, but it’s nearly impossible to tell which wall shape is which without the top face, because I check the top of the wall to help tell which way it connects (I also use the naming conventions I set up to help identify the pieces, but sometimes I still need the visual aspect). The side and bottom edges of the walls are deleted.