Using two channel amps as monos?

I'm not familiar with your amps, but are you bridging them to Mono, or using one channel of each in a "stereo-mono" operating mode?

I'm far from an authority on this topic, but I think it depends on the amp. Except for raw power output, many amps don't perform as well bridged (ie, sonically)as as the do un-bridge. Parasound published in some of their user manuals that using them in "stereo-mono" will produce better sonics than when bridged. In addition, because the power supply is only driving one channel, the power output is about 40% higher than rated for 2 channels driven.

another option is to run them in a vertical biamp arangement, if your speakers accommodate it. This would give you all of the benefits you're after - separation, and power.