The link does not seem to work for me.
Without seeing the picture you have two options (I also have 2 sofas in my room which are used but not sure of your configuration):
1. Set the system up around the main sofa (one that you use or gets used the most). This will give you the best effect, while on the sofa, as you will have to make less compromises on position.
2. Set the system up to provide some sort of surround effect on both sofas. Again depending on their relative positions this could mean having to compromise the surround effect quite considerably.
I went for the 1st option since we use the 1 sofa more than the other. Also the way that sofa is relative to the TV means I was able to set the speakers to almost the ideal placements so was able to get a very good effect.