Just my opinion, but I don't think you'd gain that much, at those listening distances and volumes, by going from the 60s to the 80s as mains. AND, I think you'd lose something by going to the 60s as rears for HT, and returning the QS8s.

Now if you wanted to go to a 7.1 config, and listen to a lot of SACDs and DVD-As, with 80s as fronts, QS8s as side surrounds, and 60s as rear surrounds..............

Jack

"People generally quarrel because they cannot argue." - G. K. Chesterton