Rob, I'm afraid that this is too late for the party tonight, but if you have an access to the official Nikon service, I would strongly recommend you to have your camera and lenses calibrated there. This is more thorough calibration on the firmware level than the AF fine tuning in the camera menu. I had my D7000, whose AF unit is essentially the same as that of Df, calibrated at Nikon service in Tokyo, which made significant difference.
Having said that, the AF of fast Nikon lenses are not particularly brisk, even in good light. So, you would have to live with that.