surround speakers question - using Infinity Interludes
 

I'm using Infinity IL40's and the 36c as my fronts and IL10's as surrounds currently. But I'm going 7.1 and wanted to figure out the best way to do this. Normally, I'd just get another pair of 10's, but Circuit City is selling the 10's at $200 each and the IL30's at $225 each. Would the extra $50 per pair be worth it?
So which senario would be best?
A:
Both: IL10's

B:
Both: IL30's

C:
Surrounds: IL30's
Rears: IL10's

D:
Surrounds: IL10's
Rears: IL30's

Thanks!!

When Sound and Vision magazine did their reviews on the Interludes, they had QPS-1 for surround spekaers. I use a pair of these in my system - which has all Infinity SMs and the QPS-1 and and totally satasified with them - although I would like to upgrade the other speakers to Interludes or Tannoy Saturns