I use "Smooth" Profile (-2, -2, 2, -2) for almost all GH2 shots. I believe it gives the widest possible dynamic range for intended color grading. However, it tends to cast yellowish tint, which I compensate during post by boosting the red in the midrange while darkening the shadow a bit by boosting green/blue slightly. Highlights are adjusted accordingly to peak at 100%.
Colorista II is used for most of grading. Below if the before/after split screen shots of what simple color grading does.
The finished version, without the split screen, is at vimeo.com/49131858

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