Don't do anything until after you have setup your system and furnished the room. Empty rooms are notoriously deceiving about how they actually sound. It's only after you've experimented with how the room really sounds and how sensitive it and you are to changes in placement of equipment/listener can you start to devise a successful plan to correct any problems.
BTW, great sounding rooms don't have to conform to golden ratios.
BTW, great sounding rooms don't have to conform to golden ratios.