To put the Engine Rooming Deck 7 and have it make any sense. There would have to be 11 decks in the saucer or you start moving the Engine Room needlessly further from the Engine Room. And there physically isn't room for it at the stern of Deck 7 in that configuration. It might work if you enlarge the ship to around 1300 to 1500 feet (yes, the curve is that deep), but otherwise it has to be on the aft end of the central portion of the deck. The corridors outside Engineering are what make it truly impossible to place it where TMoST and FJ say it is. Lower the ceiling and it easily fits on deck 6. My analysis is based on the lines of the ship and the line saying it is on deck 7. There is nothing on screen placing the Engine Room except where the entity exits in The Day of the Dove. The ceiling doesn't indicate it is close to the hull because the ceiling is perfectly level front to back which could place it anywhere in the ship EXCEPT bordering the top of the secondary hull. So if it is on deck 7 in the saucer that dictates 11 decks in the saucer and it is in the middle of the ship. Deck 7 in the secondary hull is unlikely as that doesn't fit any deck layout that matches the windows. It would be high or low in the hull, but still central. And you can't include the neck because it has 6 or 7 decks by itself which at best puts it at the top of the secondary hull where it doesn't fit what we see on screen. If you are going to be strict about details of the sets and fitting them in the ship we see on screen (at whatever scale) then you have to figure out how to change things that don't fit. Do you ignore a deck reference that doesn't fit, change the size or shape of a set or model, or something else. How Thermian do you want to be? To be as screen accurate as possible, something has to give. And TMoST is very useful because it gives insight to the layout the staff writers had in mind. While it isn't truly canon, it is close and is a nice tool to interpret episode dialog. I'm relying on it because it is the basis for the TMP layout so it links the two versions.