As long as you're running balanced out, which it sounds like you are, you're losing little if anything by using SE in.
True. I'm not expecting a huge difference. But the balanced should be a hotter signal, once I verify that the attenuators are at 0 dB. The specs in the manual don't list the balanced out voltage, but they do list the SE voltage out at 2vRMS. This should affect volume, if nothing else. I'm assuming balanced out is around 4 volts.
Besides...it's balanced! I need to at least try it that way