Thanks for your reply I was thinking the same to chop the bottoms and leave the tops a while but think I'm just going to let them go another week or so and go from there I have started to flush them. I have also heard that with sativa strains you want more amber trichomes. Is this correctIn the first picture I can see the start of a fox tail, but from what I can tell there is no bleaching (besides the white calyxes at the top). How close are the tops from the light? As I would either suggest moving the tops further away from your light or decreasing the temperature of the environment.
With the lower buds being ready before the main tops, I haven't personally encountered this in my grows. However have seen a solution, involving harvesting the lower area of the plant and leaving the main colas to continue growing (Although I only saw the grower harvest the main colas, then let the lower lying buds develop further, as they were now receiving the same amount of light as the main colas.). Undoubtedly this will stress the plant/s , but considering it is late into flower it wouldn't impact yields tremendously.
Hope this helps!
The light is not the problem sometimes but rarely my temps can reach 30° I think that's why they have started to foxtail.
It more of a personal preference, a lot of growers agree that when the trichome heads have turned milky it has reached peak THC potency. However when there is more amber trichome heads , it is considered a more couchlocked type of high. With a sativa I would generally want to see milky trichomes dominate, as a head high is a possibility instead of a couchlock , which is what most people want out of a sativa in comparison to the stereotypical Indica.
Give this post a peak: https://www.rollitup.org/t/lets-see-pics-of-pure-sativa.986992/page-2