I've made a few revisions to the design. The first one is the biggest change, though it's likely not apparent in the new renders. I began looking online to find a source for the 1/4" black acrylic, but discovered that these days, actual 1/4" acrylic is difficult to find. It's not uncommon for materials so be sold at a "nominal" size, indicating that while it may not be exactly the size listed, it'll be close. However, most of the acrylic sheet available is actually metric. It's sold as a nominal 1/4" sheet, but is in reality 6mm (.236 inches) thick. A few places do carry true .250-inch acrylic, but few carry it in black, and those that do charge significantly more for it.
While I have no problem working in metric (despite being located in the US) I find it very difficult and annoying to mix the two. Unfortunately, almost all of the styrene rod, strip, and sheet sold in hobby stores is sold in inch sizes. Which means I end up cutting a lot of pieces with dimensions like "8.375 inches, plus 12mm", which is 8.8474 inches. Or 224.725 mm.
I briefly considered using 1/4" MDF instead, but that brings in a different set of complications. All of the internal detailing would have to involve super glue or epoxy, and there would be a fair amount of finishing work on the exteriors of the sections. One (sort-of) solution would be to build the sections from MDF, then line the insides with thin styrene. I have many 48"x96" sheets of .060" styrene left over from a project I did several years ago, so it wouldn't involve any extra expense, and it would give me a nice glue-able surface inside the sections. But cutting all those additional pieces out of styrene is a considerable amount of extra work, and still means finishing work on the exteriors.
What I eventually decided on was re-engineering how I intended to assemble the sections, in order to minimize the number of oddball measurements. Originally, I intended to glue the bottom edges of the walls to the top face of the base. This creates a lot of weird measurements, though, since the base pieces would have to be the interior width (in inches) plus the material thickness (in mm.) However, by gluing the walls to the sides of the base pieces, the base pieces can be entirely inch measurements. To maintain the wall height of 3.5", I would still have to cut the pieces 3.5" plus the 6mm thickness of the material. But since all the walls are the same height, I can just set up the table saw once, and cut a bunch of strips at the right width, which I'll later cut into individual wall pieces. There'll still be some odd wall lengths, but the way I intend to assemble them, I can just cut them to the nearest number on my table saw that's still larger than they need to be, and sand them flush after assembly. Another nice benefit of this is fewer visible seams on the exteriors, since many of them will now be on the underside of each section. The nice thing about acrylic is I can take a propane torch to the sanded parts, which will smooth the surface back to a near-polished look.
The second change I made was in how the doors and doorways work. I didn't much like the slot cut into the doorway squares, or the "unfinished" look at the tops. So I added a bar across the tops that will match the black acrylic exteriors, and a similar small piece to the top of each side of the open doors. This does present a slight problem, in that the open (and destroyed) doors will now consist of two pieces, since the bar along the bottom no longer has a slot to fit into. But this is only a minor nuisance, and I think it will look better. I will just have to number the open and destroyed door pieces, so that it'll be obvious which ones go with which. I could also paint or model each set uniquely, but I don't know that I like the idea of all the doors being unique. (I can't imagine every door in an aircraft carrier or submarine being a special snowflake.)