JackdaWack has it right, pistals have really nothing to do with the plants maturity or when they are finished. Get a samll cheap handheld microscope (Radio Shack less then $15) to get a good look at the trichomes. All cloudy seems to be a minimum and some (25%) amber is a good thing.

Once you see what is happening, you can get a better idea when YOU want to harvest. You may find happiness at just all cloudy or you might think 1/2 amber is what you like.