Finish day

Umm hard to judge. Back need weeks more than front. Also 50-75% amber trichs is not a middle ground - that’s like been degrading for some time to get to that point.. and you’re losing a lot of THC potency.

Pistilis usually give you a rough estimate of when to harvest but since you have so many close fans they might turn orange and curl up sooner. A better way is to check trichomes with magnifying glass. Trichomes turn from opaque to cloudy to amber. If you'd like a head high aim for cloudy trichomes with around 20% amber (The sativa type high). If you like a body high go for around 50% amber trichomes (The indica type high). Important to base your info on the buds not the sugar leaves. Some tips before harvesting; 1. Remember to stop any artificial nutrients at least 10 days befor3 harvesting (10 to 14 days to be exact). 2. Turn off the lights during the last 36 to 48 hours so the buds fatten up further 3. A tip I haven't yet used but only heard of recently is watering with ice cold water in the final week. It causes some healthy stress to the plant which gives it that final boosts.

As Ctrellis90 says, you have to look at the trichomes to know for sure. I personally would chop it when there are no clear trichomes left and they're all milky except for maybe 20-25% amber. The more milky the are, the more "buzz" or "high" the effect will be. The more amber there are the more "stoned" or "couch lock" effect you'll get.

Without clear close up pics of the actual buds, impossible to suggest anything. The ones at the front soon, the ones at the back, a couple of weeks or more is about the best as I can judge from what you have provided.

I'm sure everyone is going to tell you to look at the trichs and when they're about 50-75% Amber ( depending on your buzz preference), that's when you wanna chop