I haven't seen my Contrivas in 3 months, but mine are just over 10' apart. I do this to avoid having them too close to my side walls. I sit at the same distance from both. They are toed in to intersect just behind my my ears which sounds just like Karelfd's solution.
The distance the Contrivas are from the side walls and from the back wall, I have found are critical to the bass response. I measure the distance from a point between the woofers and the floor and multiply it by 1.65 which can be the distance from the back wall to the face of the woofers or from the center of the woofers and the side walls. Whichever you use, the other distance is then 1.65 times that distance.
The distance the Contrivas are from the side walls and from the back wall, I have found are critical to the bass response. I measure the distance from a point between the woofers and the floor and multiply it by 1.65 which can be the distance from the back wall to the face of the woofers or from the center of the woofers and the side walls. Whichever you use, the other distance is then 1.65 times that distance.