Another 2-3 weeks or until there are about 90-95% brown pistils and this will give you flowers with peak THC levels and a mind bending head high.
If you prefer a sleepy and relaxing CBD body stone, harvest when there are 98-100% brown pistils.
Pistil colour is more representative of plant health and it is plant health that determines trichome cannabinoid composition, where as trichome colour on its own does not.
Besides, some strains will never have amber trichomes and others will have 75% amber trichomes after only 4 weeks of flowering, illustrating how judging harvest timing by trichome colour alone can present problems.
Hope this helps, Organoman.