I would recommend against it as well. Not sure driving that configuration with an AVR would be safe. You could do that if you have to cover multiple rows, and use external amplifiers. Which way is the layout going to be? Imo you don’t need to worry about .6 Atmos in a room that small. Plus, there are issues with some soundtracks using/not using either the middle pair, or the front and rear tops. Also, if you’re going to be seated against the back wall, a 7ch bed, and rear heights/tops will not be very effective. If you have room behind you though, that would be different.