Harvest when? And what to look for.

Looks like you have a long way to go yet. Where are you now - week 3 of flower? Your buds haven't even begun to really form so you look to have at least 3 weeks to go. To time your harvest, there's no substitute for even a cheap $20 jeweler's 40/60x magnifier. With that you can see the trichomes, and the degree of cloudiness that develops over time tells you when to harvest. If you want more CBD, once you get to the harvest window (in 3+ weeks) you wait for the trichomes to become fully cloudy and turn amber. As more turn amber,THC falls and CBD increases and you can chop when they've reached the balance you're looking for.