Just as an exercise to improve your prediction skills that's fine, but otherwise don't worry so much. Simply obersve and react when appropriate. Worrying about predictions may bias your trigger to harvest.
cloudy-milky-amber is actually the poitn at which thc is no longer increasing and can only go one direction after that. the rease we want 'some' amber despite that fact, is for the sake of the entire plant's ripeness and not just the top colas. You can also choose to take top colas down and let the rest ripen longer if you wish. I have done this but don't see much value in it. Don't do it expecting to improve yield of lower nugs, just a more even ripeness is possible. It also won't turn a larfy bud into anything better.
The exact point is 100% personal preference. these look quite ripe, so i'm sure you'd be fine at this point. The hairs seem long but they are all rusty (aka dead, not a bad thing), so maybe a little more fattening of calyxes is possible? I'd trust the trichomes at this stage.
If you want to experiement with early-middle-late harvests, take some buds off at different points over 5-10 days.. depends on how deep into harvest window you already are, of course, but 'next' time can try any point you wish, label it, dry and cure it, then test. In general later harvest is more of a sleepy buzz, but your mileage may vary. e.g. nyquil makes most people comatose, but some get hyper. It's worth it to figure it out for yourself.