how much longer?

It's hard to say without a closer look at the trichomes. Based on the pics you've provided I'd guess 7-10 more days. I highly recommend getting yourself a jewelers loupe or a digital microscope so you can look closely at the trichomes. When you start to see some of them turning from cloudy to amber you know you're close to harvest. At that point it just comes down to how "stony" you want your weed to be. More amber = more of a heavy, sedating high. Less amber = more of a mental, functional high. It's all just personal preference at that point. I personally like to aim for 15%-20% amber but I like my weed to be a little sedating.