Hello @ataylor, welcome to the Sonos Community!
I believe nothing much can be done for this scenario. If you mount them up on the wall, it won’t be high enough to make a difference. It’s also tricky because the higher you mount them, the worst would be for your listening position.
Surrounds are meant to be placed behind the listening position, and seeing the attached picture that would not be the case.
However, you are the only one who can try and see if a different position works better for you.
I have my Era-300s (a Stereo Pair) sitting on top of my workstation, 20 inches from a flat ceiling, 18 inches above ear level. They are about 3 feet apart and three feet from my ears. No other choice for positioning them.
I did play with the height channel settings until I was getting a pretty decent ATMOS effect. I sure hear the difference in imaging between a HD track and Atmos track so I’m getting something sounding pretty good from the setup.
