Do you have a kill light? I will let you borrow my green LED if you do.
Don't forget the brightness of the night (Moon) and weather (Fog, Rain, Snow) will also dictate how well you can see with certain colors. I think green is the best for light fog. Red for dark nights and amber for snow cover. Seems like to much bother so I stick with red all the time. Might give white a good try this year.