In my G7, I am using -2 for contrast, and -2 for sharpness. So far, in shooting landscapes at dawn and dusk, I have not seen any blown highlights. Of course, it is necessary to check the histogram foten, just to ensure a "healthy" exposure.
I approach shooting the G7 the same way I do when scanning slides; I try to make sure I get a histogram that I can work with later on in Photoshop.