Hi, so I personally always harvest when 80% of the trichomes on the flower buds are milky. The sugar leaves turn amber faster, so I go by the flowers. And just in case you didn't know, when the trichomes change from milky to amber, the THC is converted into CBN. Its effect becomes less but more narcotic, so it depends on your preference. More THC is milky, more CBN is amber. Good luck with the harvest!