Hey Kwackperson, part two...
I kind of misread your first post, thinking you were wanting to level the level during record. Now I see you were talking about mixdown. My other post still holds true, and is the best way to get consistent level, which is a different thing to what we normally get a compressor to do. We are talking microdynamics versus macrodynamics.
Usually we use compressors for control of microdynamics, that is, we want to control a sudden peak on one word or note or beat, that sort of thing. That is why we use fairly fast settings, like peak detection and fast release, so the unit is quickly ready to work on the next sudden peak. What you were talking about sounds more like macrodynamic control, where you are after consistent levels over time. For this you need much longer settings, release in particular, but also RMS detection rather than peak so that average levels are looked at and adjusted. The "classic" Teletronix LA-2A Levelling Amplifier is a case in point. We think of it as a compressor, which it is, but because it uses optical circuitry it doesn't react very quickly. Driven conservatively it gives a smooth ride, especially with more pad-like sounds. If you are more aggressive with it, the slow attack will let the "pick" of a note through and squash the body.
Anyway, back to your mix. Use the compressor to catch the short, microdynamic peaks that jump out at you, then write automation to govern the more broad-brush level changes. Whatever methods you employ, make sure to let some random movement remain, otherwise your tracks will lose their interest, kind of like this long winded post...........
I hope I'm making some sense.