When you get to the point where the colors start dropping below M, then we would only recommend these colors if you or your fiancé are purposely looking for shades or hints of color that are observable in the face up position.
Here are colors N, O and a fancy brown along with colorimeter readings below.
N Color
Here's a D next to the N face down and face up.
O Color
Fancy Brown/Yellow
To learn some valuable tips for observing color in a store and other important things check out the tips section.
