I have the HD800/WA33 as well and use both, H impedance & H level.I wonder has anyone experienced with HD800 + WA33? I usually turn the level to H and impedance to H and I feel I enjoy this setting more than level to L and impedance to L. While I chatted with WOO they L level and L impedance is enough to drive HD800?
Remember, there's no 'appropriate' setting for the 'level' with any headphone, just a matter of preference.