Clever Models Gateman Tower, Test Fitting Sub-Assemblies

I am 5/8ths done with the upper tower walls and windows. 

Here's what I have so far, roughly balanced together in order to see if I've screwed anything up.

My original plan was to light the inside, but at this point, that's too much of a hassle. I did sandwich a layer of black cardstock between the outer and inner surfaces, so if I do light it later, the light won't shine through the walls.