I can't tell you the distance. Others will probably be able to give you illumination levels that are in the right range. Those you could measure with your light meter. Without that, you'll need to tell people which bulbs and what kind of reflector or spot they are in. Wattage? Bare bulbs? Spot bulbs?, etc. Then maybe they can give you examples of what they have. But illumination levels are the best way of doing it. I've seen that data before on the web. Why not google it and see what you get?