Same as the others. Personally, more amber so 1-1.5 weeks.
To add another point of view:
"Purple Berry Muffinz Feminized has an amazingly short flowering time of 45 to 55 days."
Of course we check trichomes, but why not cross check with the theory ;-)
If you are still feedind as described (1.4l/d), she somehow is thirsty, so there's still progress happening?! However, I would slowly reduce watering, so she knows it's coming to an end 😋 and wait for 1-1.5 weeks.
Happy harvest.