I am upgrading my home theater system. When it was installed in 2001 it was set up as a 6.1. Due to depth constraints in the walls the three rear speakers had to be installed in the ceiling just behind the main listening spot, so I don't have the option to move them. I was looking to purchase a Yamaha receiver with Atmos and YPAO to help. How should I wire up the surround? What should I do with the rear center speaker channel for the best sound?