Harvest timing?

At least 4 weeks, maybe even 6 going by these pictures.

So long you shouldn't worry about it day-to-day. Several weeks for sure. Don't trust the breeder's estimate of flower phase.. only trust what you see in front of you. When they calyxes stop plumping around the white hairs and when most of the white hairs are rusty colored, then you can start scoping the trichomes (on calyxes only). If you don't have some sort of 30-60x magnification, look into a jeweler's loupe or currency checker. They can be very cheap, but find one with a glass lense and read through comments on the product listing page. You'll probably find some growers commenting on its effectiveness for this specific task. I know you will if you use amazon, lol. I'm one of several that has commented there on a couple different magnifiers..

You are at the beginning of this journey, so be patient. Sativas tend to bulk up later in flower. I'd say at least 12 weeks, but probably closer to 14. **I've never grown this strain myself, this is just my impression based on a single photo.