I would question whether the "ghost ball" is the "very best way to teach aiming to beginners"....if advanced players can't see "ghosts," I'm pretty sure beginners can't either.
From what I've read and experienced the ones that try to explain "ghost ball aiming" are the ones that don't understand how the aiming process is really working. I do understand that you use the "ghost ball" to show an example of what's happening when the cue ball contacts the object ball (and this can be explained to beginners, but only in theory, not in practice).
I'm talking about using the "ghost ball" to actually play the game with....this is difficult to relate to. I know many pros claim to not know what they're aiming at or their system, this is different than saying they aim at something imaginary.
Find the "authority" on ghost ball aiming and I would like to debate this topic in a professional manner. They can explain what they're doing and I'm free to ask questions that they must answer and I'll explain what I'm doing and they are free to ask questions that I must answer. This is completely fair, and would be very educational to those that are interested in knowing.
....or imaginary balls or whatever, I don't even understand how this can be described with a straight face.
'The Game is the Teacher'