I suppose good levels aren't really the issue hear anway as 24 bit recording as a ridiculous amount of headroom. I hear what you are saying. And yeah i wasn't planning to mix on the thing, I just wanted to be able to evaluate mic placements on the fly. You've been very informative, thanks.
Edit - If I were to buy a pair of the etymotics, which are high impedance, would you recommend any amp in particular?