Dungeon Architect

I think I’m really close. My dungeon event listener changes the theme (candy V2 in a medieval dungeon … LOL) inside my runtime dungeon.
I get the furthes room cells (Room A is my entrance and room B should be the exit or another place of interest) … the cell dimentions “out center” of Room A is the place where my dungen theme override volume is.
But how do I get the correct scale for the override volume? Is scale Z even possible? (I can use a very huge Z value for now …). How do I get the rooms X and Y dimensions?