I think its wise to know what it should look like \"technically correct\" and use that to influence how it is painted to look right as a painted miniature.
ie the figure will look better if it is painted how we think it should look as opposed to how it should look if real.
Basic rule is that if a face is perpendicular to the horizon it will reflect half sky half earth.
If it is facing downward by more than 5 degrees it will reflect only earth. 5 degrees up only sky.
0 to 5 degrees and the horizon level on the face alters up or down to suit.