Man, taht are some very nice buds you have there 1-2 weeks should do it Lookin' forward huh grtz El_jalous
One way to tell is by the trichromes. When their heads start to turn murky, instead of clear they are at maximum potency. This is the most accurate. You can also wait until the pistals are 60-80% red and starting to die. They will curl down and get clumps of resin on them. It's really your preference when you harvest but I agree with everyone else here that they will look a lot nicer in a couple of weeks. Here's a pic of some trichromes I have in my garden