Short version.
I had four QS8s for my (previously) 7.1 setup. It was great.
Dolby (highly) recommends mono-pole speakers for all locations in an Atmos setup.
I traded in all of my QS8s for on-wall M3s. It really helps Atmos (and DTS:X) to better pinpoint sounds within a 3D space.
Longer version:
Atmos uses sound object within movies, and it takes multiple speakers to create those object to defined points within the 3D space of your room. Using bi/di/quad-pole speakers doesn't allow a system (receiver or pre/pro that is processing the audio) to use pinpoint accuracy to create those sounds since they are designed to spread the sound all around into a surround space.
With all of that said, I am not saying that it couldn't work or even work well, but when I specifically asked a Dolby tech at CEDIA back when they announced Dolby Atmos for the home about bi/di/quad-pole speakers, and he really said that it was "less than ideal" and made sort of a grimacing face. That alone was enough to convince me to change out the speakers from quad-pole QS8s for mono-pole M3s. It cost me my four QS8s, a VP150 (I had upgraded a few years earlier to a VP180), some Axiom Bucks, a sale price, and still some money to do it, but in my opinion it was worth it for me. It may or may not be for you.
Keep in mind that you can always set things up with QS8s for now and see how you like it. You would need to lower the surround speakers either way, so that needs to happen regardless of the type of speaker, so you can try the QS8 setup with Atmos without any additional cost.
