(please excuse my bad English)
Wow! Splendid room and system, really.
Don't regret the dedicated room, which moves music away from the place you live (your *living* room). I have a dedicated room... Sometimes I miss the music in my living room.
High ceilings are fine. And you have records in the back, the act as diffusers. Maybe some absorption behind your head.
One thing you can consider is window thick velvet curtains that you shut in the evening.