More difficult than meets the eye

What color to do the exterior of 747? That is the big question right now and we have to make a decision soon. After months of looking at every house in Minneapolis and about a dozen samples, we are down to 3 options. As you can see below they are all versions of off white and you would think it would be easy to choose, however as you analyze the options they start to take on different hues. One becomes more warm, while another has a bit of green and then yellow starts to creep in, and then based on the time of day the amount of sun or lack there of changes everything.
Is this house Natural White?
Is this wall Dover Sky?
And last but not least my all time favorite home on the lake...is it Light Grey?