That's close to the basic understanding I get from the recommendations too. Though I believe your estimating is a little off. As I understand it, it should be more like this:
Crystal clear: too much water, ok to cut back some
Almost transparent: well hydrated, keep it just like that
Light yellow: slightly dehydrated, you should probably drink more
Yellow: dehydrated, you need to drink a LOT more.
Dark yellow: severly dehydrated, get yourself to the hospital.