I say green. The reason I say this is because, my friend and I fish river walleyes in the spring at night when they move shallow and feed. Shallow enough to see their eyes glow. When I used a red light they didn't seem to like it and swim away. My buddy had a green light and they seemed less bothered by it. For him they would slowly swim by and not freak out. My red light they would tend to scatter.
These are my observations and others may vary, but when I use a light now it's green.
When I set Tip-ups I'll use the white light if I need to see better. But I try not to shine it down the hole. If there is good snow cover the color of light probably don't matter much as long as it's not directed down the hole.