If you really want to know the answer to this, you should read the "Deep Space Nine Technical Manual", written by Herman Zimmerman and Rick Sternbach. It completely lays out the work Starfleet did to upgrade DS9.
Then the following links are definitely NSFW for you, friend:
https://www.amazon.ca/Star-Trek-Space-Technical-Manual/dp/067101563X
https://www.amazon.ca/Star-Trek-Generation-Technical-Manual/dp/0671704273/
I'll throw in this one if you're feeling particularly adventurous one evening.
https://www.amazon.ca/Klingon-Bird-Prey-Haynes-Manual/dp/145169590X/
Do you have the DS9 Technical Manual?
I'm more interested in this
The official Star Trek: Deep Space Nine Technical Manual has quite a few cut-aways, partial floorplans, and maybe enough detail for you to extrapolate a full floor plan for your use.