I'm an Electronic Engineer (well my two degrees say so at least). I don't need no stinking online calculator.
It's fairly simple. 93dB/1W/1M = 16W maximum for 105dB continuous (at only one meter so you have to extrapolate for losses to your given listening location). But then it's not supposed to be 105dB continuous either. That's peak. At 8 feet from the front speakers, it's probably no more than 20W each for peaks at 105dB for the 5.1.4 relative speakers. The side heights get 60W each (no sharing as they have their own amp). I think my surround #2 speakers get 40W each (no sharing as it's a separate amp). The rest of the speakers are split between two AVRs (the 7012 and my old Yamaha using 7.1 external inputs with 7 on the 7012 and 6 on the Yamaha) so they probably average around half the max rated load they'd normally see. I'm going to guesstimate they get at least 50W each continuous power with peaks over 100W. So even with ECO robbing the system of like 20% of the 7012 power at all times, it's never going to stress the system. The Yamaha is not running in any kind of ECO mode (it never really gets hot as-is).
Probably somewhere around there, but I'm using only 6 of 9 on the 7012 and 6 of 7 on the Yamaha. I've never run out of power in ECO.