How big is the sweet spot for the vandersteen quatro wood CT speakers?


Just fell in love and purchased a pair of Vandersteen Quatro Wood CT speakers. Going to be set up in my living room approximately 13 x21. The speakers will be 13 ft apart. We'll have two chairs. Our heads will be 6 ft apart  and 18 ft from the speakers. Has anyone had any success creating a sweet spot  that wide (so 2 people are in it)?
groomer159
Oh...Johnny R is doing the setup. Your in awesome hands.  I had a very challenging setup and Johnny spent like a hour setting up my Vandersteen Treo CTs and boy do they sound great.  Seat back watch the show and afterwards listen to the magic. 
Thanks for all your feedback. John is amazing. Came and scoped out my living room and we decided to put the amp in the basement so it wouldn't be that far away from the speakers. We even checked to make sure the amp and preamp would be on the same split on the breaker box. Talk about being thorough. Can't wait for the speakers to come in
@OP, are you going to leave the amp on continuously?
@miketuason ,
If your 'sweetspot' is only 6 inches, I think you need to do some adjusting.
Bob
The amp will turn on when I turn on the preamp. The chairs are set so our heads will be 6 feet Apartment 6 in