Haven't done a mild. I leave my kegerator at 55o, and vary the pressure based on what's on tap. I checked my notes, I've kept the pressure between 8 and 12 psi. (1.6-1.89 vols)
Yes, sometimes you don't get a decent head on the beer, but the way I see it that's akin to pouring from a beer engine that doesn't have a sparkler. Cracking the tap open gives that "sparkler" effect, and really changes the taste of the beer.