Devore 0/96 and Room Size

I don't have the O/96 but auditioned them a lot.  My room is 15' x 13' with a large room opening in to a hallway.  I've had a number of big floor standing speakers in there, but the O/96 is one of the few that had me wondering if they'd work in my room.  They are pretty rich in the bass and definitely need space from the back wall.

What's your overall room size?  You mention 15' deep, but I don't think I see the length or height. 

I am building a new home and did call John regarding the 96s in a room 14 wide x 16 feet long with 10 foot ceilings. He said the 96s would be wonderful in this room. My room is very close to yours it seems   

I love my current Fyne F704 speakers, but not sure they are the best fit for this new room. They are huge! The 96s intrigue me. Finally decided I will try my 704s in the new room first as they may sound great with room treatments.

The room is 15 x 19.5, and the ceiling slopes from 7.5 to 9.5 ft. My intention is to place the speakers along the 19.5 wall at the 7.5 end.

I see. The room is plenty big for sure. Placing the speakers on the shorter 15 foot wall would be best, but it seems the ceiling slope direction is the real issue.