Sorry--no personal experience. My ducks lay white/light green eggs. But I do know that even with the light colored eggs, a couple things make a big difference: The darkness of the room, and the brightness of the light. If you can find a TOTALLY dark room, that is great--otherwise, wait till night and go into a closet with the light turned off. Try to get a really bright flashlight or other lightsource to work with. I was really surprised the first time I candled at night how much more I could see, versus a dark corner of the basement (but still with some natural light) during the day.
Good luck!