You are seeing amber trichomes ok but how much ? 10% or 80% ? What type of effect do you wanna experiment ? Deep stone or energetic high ? You should answer all these question before even thinking about flushing and harvesting. I can tell you by the size of tour buds that they can still gain weight and be fatter. And about the hair changing colours it is not really something to monitor , it tells you that the time of harvest could be close but you can have 70% of red hairs and still not the trichomes ratio you are searching for. Leave it longer would be my recommendation , the gorillas strain are know to be ready around 8 to 10 weeks of flowering. I would have wait one more week then 10 days of flushing and cut