I have had some old school strains that easily went 4 months into flowering before being ready for harvest. A lot of Sativas will never get the trichomes to be totally "right" because they continue to grow during flowering, and new pistils aren't uncommon. New pistils = newer and less mature trichomes. For the first time this year I used a finishing 10K MH bulb for the last 10 days of flowering and I was skeptical at first, but it matured them very quickly. I don't know if it was the blue light or the increased UV, but they finished suddenly. This is from a 35+ year old strain that is mostly Sativa, but not all.
To me, your plants look great and I think that they could be harvested at any time with great results. If you see the beginnings of foxtailing, you know the time has arrived. I thought I might have seen the beginnings of it on some buds, but I can't tell for sure.