How much longer?

Without 30-60x magnification, it's tough to guesstimate such a thing. Great thing about hydroponics is you can 'flush' in 24-48 hours. without a magnification and no familiarity with your strain ... generalization of 50-75% of stigma turning red/colored is one way you can choose when to harvest. i'd google this stuff and read teh 1000 opinions on it... test out early vs late harvest and decide for yourself what you like best. So, no worries if the first harvest isn't where you want it in future... as you'll need to test it to find out slowly over time... i still don't know my exact preference yet. get a cheap loupe or nice digital microscop to see teh trichomes. watch how they progress the last ~2 weeks. once they start turning amber in earnest, it's a 3-5 day window probably... seemingly takes forever to get from a few ember each locale to a wave of it washing over more quickly.