TS600 FastBuds OG Kush Auto

Whats 40cm in inches :P ok google says about 15" That's decent. It's possible to go 12" sometimes but thats dependant on diode count and intensity. Not all lights are created equal. 40cm is good though, you'll be ok. Just keep watch cuz the plants will grow up to it and if you don't monitor regularly, you'll walk in one days and your plants are 6" from the light and are blotched with white from light damage.

Only start flush when my thrichomes are at my desired color. Everyone has a different desired effect. But a 60x jewlers loop Look at the thrichomes on the buds. Not the sugar leaves coming out of the buds. For a sedative body high couchlock flush when 30-40% are amber orange color For cerebral head high that's uplifting harvest when all are cloudy and no clear thrichomes. For a good middle ground smoke Harvest when 10-15% are amber and the rest are cloudy. Pistol hairs can be misleading. Most strains have 2 and even 3 sets of hairs. They will grow out and white then turn orange and brown then new hairs come in. If you harvest when the first set are brown then you may be harvesting way to early. This is why you check the thrichomes and start flush when they are the color for your desired effect. Goodluck