I wouldnt pull those leaves, they will still use the goodness stored in them. Also sone autos wont amber really, so ya gotta go by what the plant looks like sometimes. Muddy has a good harvest guide. If ya want the most outa your plant wait till vert growth stops and go to bloom but I am going to try bloom nutes in my flash babylon when I see sine preflowers and see how it goes and if she finishes around 45 days like the pack says. Im thinkin no cause im 20 days in and no preflowers lol.