THIS time I'm with Capt. Guzzler. Hr doen't mean a three degree slope on the centreline he means a three degree descent on horizontal flight path be it curved or otherwise.
It basically means that you begin descent where ever a normal, three degree descent will have you rolling out on centreline and glideslope.
Now that I've given you one GG, I'm still at issue with your terminology. Visual VMC? If conditions are less than VMC, they are IMC, regardless of what you can or cannot see. Therefore any time you circle with less the 500ft vertical seperation from cloud, you are carrying out Visual circling inIMC conditions . If conditions weren't IMC, you wouldn't be bothering!