Id prob go with a AQ2200 if your going down to 1 ohm. I like pushing my speakers to around rated, never really under but not trying to overdo it..There rated at what 1000? So anything around 1000-1200 would be fine. Still get the most out of them but alot more longevity.
And yah those subs will only need like 4-5 max each, id say. Most circular 15s need around 3-4 ported on the low side so I guess 6.6 doesnt sound TOO rediculous altho a little big.