Hello Sandor,
I tried some times to paint the white in the eyes of 30mm figures but to me it don´t look well.
So I stopped with that and followed what you mentioned that the eyes mostly lies in shadow, for me this gives a greater effekt.
This will work with 30mm but I´m sure it is a quiet different thing with bigger figures.
It´s a different thing with horses, normally you don´t see any white in their eyes. But I used to paint their eyes with a little white. Not to show the white of the eyes, more to show the light reflecting in their eyes.
Hope this helps,
Christoph
Christoph