I just looked at your Polk 700, IMO that is way too much speaker for rear surround use.
I’m talking about 5.1, small, not a real home theater, yours will be bigger than mine but you mentioned one chair.
I am going across the 14’ width, my small rears are laying on their back, shooting up, using the space between the back of the high back sofa and the wall 8" behind sort of like a channel or horn, volume adjusted with the AVR. This is where my feet are
Many, perhaps most people boost their rear too high, it is best when you are generally unaware of the rear, until you turn them off, then the image collapses forward.
A sense of space, but not generally aware of them unless specific content put there by the director for a REASON.
I have many Movies and Music DVDs, and I often watch streamed Music Video, the Voice (it’s all over the world, hop about on YouTube, search Voice, Voice Battles, Knockouts ... American Idol, America’s Got Talent, Donna watches Dancing with the Stars.
Sometimes whatever it comes on with is good, but often I change to Direct, or try 2 Channel Stereo and it sounds better. I don’t know what the original was, what a station or cable company or AVR or TV might have decided to do, so get in the habit of occasionally going for ’Direct’, you might find it turns some pseudo surround off.