7.1 setup vs. 5.1 with 2 extra fronts?

[Jmobie]

Hey everyone. Our family home theater, using the components shown in my signature, had to be disconnected, undone if you would, and taken out of our "theater" room because we are having wooden floors installed this week.

Anyway, since I prefer the RX-V663 to decode the HD codecs instead of the S560 Blu-ray player (I'm not sure there is even a choice in the S560 setup), our surround backs are rarely being used during movies with TrueHD and DTS HD MA. I should also add that two Infinity Primus 162 bookshelf speakers were being used as our fronts because a space issue, two Yamaha NS-A1638 towers as our sides, and two Infinity Primus 150 bookshelf speakers as the surround backs. The 150's are an inch or two smaller in height than the 162's.

My question is would it be better to take advantage of the size of the Yamaha towers and use these as an extra pair of fronts? Then the Primus 150's would also be used much more as the surrounds instead of the surround backs.