I seem to remember reading an article written by a (then ) RAE (Royal Aircraft Establishment,F'Boro)boffin. He had done a study of a number of Air - Ground gunnery ranges and concluded by scientific measurement that the then black and yellow chequerboard painted buildings, at a certain(??) distance are perceived by the eye as green. (What colour do you get if you mix yellow and black - Surprise, surprise).
I just thought this might be relevant??
I reckon dayglo orange, added advantage, it matches your eyes.