Help w/ Surround Back Speaker Placement

[Kali157]

I currently have a 5.1 system and am looking to expand to a 7.1. My problem is that my theater "room" is about 12' by 12' and the main seating couch is only about 5 inches away from the rear wall. My Left and Right surrounds are currently ceiling mounted.

Now since the seating position is so close to the back wall and I have a window covering 60% of the back wall, How can I mount the rear surrounds? Can I mount it on the ceiling directly over the couch firing straight down? Or firing straight down but slightly behind the seating position?

This is another option. My ceiling is about 9 ft high. Should I place the rear speakers on the rear wall and near the ceiling around 8 ft up? I was thinking of having them pointed straight forward.

Any help would be greatly appreciated. Thanks