As I remember it Posnansky was certain that the 'tears' was a way of showing how the eyes of the sun gods were quickly moving, not really tears at all but 'movement'.

That may be so. However, 'quick' means 'full of life', the opposite of 'still'. Remember that vai ora a Tane combines the idea of water with the idea of health and vigorous life.

At the archeological site of Orongo (Heyerdahl 4) was found two paintings of faces, similar to those on ao paddles:

               

In the left painting no sign of weeping eye appears, the three rays from the eyes are that, nothing more, and they indicate light, not darkness. In the right painting there might be an idea of a limited season (* 2) and then - why not - a similarity with the 5 dark nights on the sun god at Tiahuanaco.