One unit equals 1 cm but is it usefull?

You said it. “…make it look as accurate as possible.”

Some of this will be realistic and some of it will be exaggerated. If it looks right and feels right, that’s all that matters. You may have to fake a few things to get it to feel right but I would build out a hall and a few rooms to scale then adjust them to “feel right” (like RS mentions below).

You are on the right track.