Is really very interesting information you give us in your post, @ladyrebecca. Although blue is one of my favorite colors, I can understand that it has not been perceived as a color of its own by the ancients, if those conjectures are true. When I consider that in several passages of Greek mythology, the sea is associated with the bull, it occurs to me that the sea was not seen as blue, perhaps more towards black.
My eyes at the moment (I have some discomfort in them) do not allow me to do all the proposed exercises, but I do know that in my "inner vision" (to call it in some way), that is, the one that occurs with the eyes closed, only the blue appears when, in meditation, I center the force of my eyes (I concentrate) towards the middlebrow, in that point called "the third eye". That has always seemed very striking to me.
Thank you for your post. Greetings.