We use the light to illuminate buoys when running at night, mostly. Candlepower is good, more is better -- I use a 250,000 CP unit from Hamilton Marine:
http://store.hamiltonmar...m/browse.cfm/4,383.html
I have personally never had good luck with electrics to control the light. I like to have a hand on it. I only run at night from the upper station, since it is hard to see out and see the buoys from the lower. So, I have no control of the light down there.
I am sure that other members have different experience, and can recommend lights that work for them.....
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida