Hi Beth,
I recommended the same Omnimount ceiling mount to your Dad. His installer said they don't care for the Omnimount, but I talked to Brent at Axiom, and he said they recommend Omnimount all the time.
Here's the problem though. If you have the threaded inserts in the back of the your QS8s, Axiom recommends the Omnimount 10 lb. model because the threaded insert in the QS8s is sized to fit the 10 pound model. The 20 lb. model won't fit the insert on the QS8s.
Axiom says the 10 lb. model holds the 11 lb. QS8s just fine. HOWEVER, if you'd be more comfortable with the 20 lb. model, it comes with a plate you can mount on the QS8s rather than use the treaded insert.
Here the best prices I've found for the Omnimounts. Do you own search to see if you can do better.
Omnimount 10.0
Omnimount 20.0
My advice is to call Axiom, explain who you are, and ask what they think. They won't steer you wrong.
