While there is some good info in your link, leaves can yellow for a number of reasons that have nothing at all to do with readiness. The same goes for the pistils turning brown. And the same goes for the smaller leaves drying out. Too little nutrients, wrong pH, wrong nutrients, too much water, too little water, too high temps, etc can cause the symptoms the author mentioned, even when the plant is not close to done. So maybe on a plant that has been taken care of flawlessly can you count on these ripeness indicators, but for most of us, I think checking the trichomes is still the best way.