Good question on the oxygen rate, since we can't measure it as home brewers. My understanding is that just shaking the carboy maxes out at about 8 ppm oxygen. I think this is generally regarded as barely adequate for all but lower gravity beers. So to me, low oxygen consists of just shaking the carboy, and perhaps not as thoroughly as I would normally do. If I want high oxygenation, I'll hit the wort with some pure O2.