When having 3 wards up...

I think that when you have 3 wards up I think the oldest, or first ward placed, should have a different color on the mini map. The reason I would like to have this is so I can see what vision I'd be losing in order to gain vision in another area. However I don't know what color should be used to keep things clear and for clarity purposes. I feel like green might be a good option, although I prefer the white version. White - http://imgur.com/ISwoVSW Green - http://imgur.com/4W5tNUh