I read the double image wrong for a split second creating a interesting effect.

I saw the elevator tube at the bottom of the original picture connecting with the one on the bottom of your mockup giving me the idea of raising the ceiling higher so the gantry connected to the new higher ceiling via longer struts.

You'd then be free to remove the ceiling from this shot and show more of the throne room space behind.

Naturally it would mean having to alter every shot with the ceiling in but it would make the space more open and less blocked off in shots like this one.

The walkway also looks a bit bowed to me (or is it a trick of perspective?).

Does that walkway have any connection to the stairs (my memory is getting a bit shaky these days)?

If not how are non Jedi meant to use it?

Where does it actually go?