Harvest half ?

Heya! Imo I think they have a bit longer to go. If you judge by the pistils usually 70-90% ambered is a good time to harvest. The best way is to use a small microscope or jewelers loupe to have a glance at the trichromes. Most people harvest when all the trichromes are milky to 30% amber. If you harvest with more milky trichs it will produce more of a head high effect, where as more amber trichromes will give you the couch lock effect. I would suggest looking at the trichs if you can, I have had plants ready to harvest with lots of white pistils left still and some where they were all brown. In regards to your question, I have harvested tops of plants and let the bottom sit for another week or two without any issues. I have always just cut the branches off where needed, the plant wouldn't be using those upper plant growths anyways for the lower buds. Lots of growers do this to achieve the same effect from all the buds. Cheers and good luck!