With CBD plants I go when trichomes are 100% cloudy, or right at the first sight of amber. Pistils and density of bud mean nothing, the ripeness of the trichomes is what matters. I have had the best cases with chopping at full cloudy. My canna-cheese 1:1 was harvested with 5-10% amber and has been doing wonders for the hubby (seizure free for almost a week now). I will be updating my thread with info on it. I have harvested a pretty large number of different auto cbd strains and their pistils dont flow with the percieved ripeness of the pistils. CBD plants are about maximum efficiency of cannabinoids and terpines before they breakdown since breeders test their strains directly after harvest, or shortly after dry.
Hope I helped