For a room that size (ie relatively small) I would definitely go with the QS8s. Assuming you are mounting the speakers at the sides (rather than on the back wall) the left QS8 tweeter will still bounce off the back wall and give you that ambient effect.

I'm not 100% sure, but I'm pretty sure that it's the tweeters where the bouncing is important... the woofers are just mounted top and bottom because there is no room anywhere else in the cabinet

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8