My room dimensions are 10.5 x 27 x 7.5
I have 2 rows of seats, the centre of both rows sit 9 & 12 feet from the mains and the QS8s sit about a foot behind the second row on the sides.

I don't think your room is too small, either one will do.
I always try to buy a little bit bigger than I need, that way I know I will have no short comings from the speakers.