I drew illustrations for my book which I mentioned in the last posting. The third eye I am talking about is the brow chakra of the yoga system. It only manifest between the eyebrows. That is its location. The subtle eyes are on the subtle body and they are superimposed into the physical eyes when you are awake and they are experienced in astral projection and lucid dreaming as regular eyes on those levels.
Don't expect that everyone will agree on what 3rd eye is or how it functions. Each person might define it different.
I am giving the standard definition according to yoga and by my own experiences as a teacher of kundalini yoga and a person who has maintained a meditation practice for over 30 years.
As for the subtle eyes, if you were ever in a lucid dream or astral projection, the eyes you were using them are the subtle eyes. These seperate out of the physical body while it sleeps. And they are again fused back into the physical system when you are awake.