The tweeters on the QSs should be firing to the front and rear of the room. You don't have to position the side direct radiators the way you've shown. You can point the drivers slightly away from your listening position to diffuse the sound.

I've had direct radiators as sides and I would never recommend them over the QSs.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated