As mentioned I wouldn’t get to worried about exact angles especially with the QS8s. The best thing I’ve found is to play around with positioning since no 2 rooms are the same. If you don’t want to play around with placement then anything close to the Dolby diagram or this DSX one will work fine:

http://www.avguide.com/blog/playback-learns-about-audyssey-dsx-part-3?page=1

3M80 2M22 6QS8 2M2 1EP500 Sony BDP-S590 Panny-7000 Onkyo-3007 Carada-134 Xbox Buttkicker AS-EQ1