Well, my two cents.
In any recording I aim for low enough volume to 110% sure of never going into clipping. Digital clipping sounds awful. On the low end, I want to stay off the noise floor. And since the 722 has a decent S/N, it seems quite OK to aim between -20dB to a maximum of -10dB for the peaks. Exactly where the meters are the most detailed.
Once the recording is done, I transfer it to my PC and do a "normalise". This will set the absolute peaks to exactly 0 dBFS by increasing gain. Generally I will do a bit of compressing as well, but that depends on the source and the sound I aim for. When aiming for that contemporary CD sound, it would include going into a limiter set at -0.3 dBFS.
Gunnar
Yep, you're on the money here! Headroom is good. There are only 2 reasons why people generally run so hot that they risk clipping. Either they don't want to do any 'post' work (the common taper reason) or the pre's aren't stellar. Just run the levels lower and do some post. If the arguement is that post processing degrades the sound...then just do a 'peak normalization' and it won't do anything destructive.....really! This is how the pros do it.