Some strains won't turn amber - historically "sativas" if that was true or an urban myth i don't know. By this point i'd say the inter-breeding throws all that out the window.
A lot of this will be personal preference as to the exact point you harvest. When i grow clones, i harvest the day before i observe what i want. Some development takes place after you cut it from the plant.
I'd watch it every day until you are really comfortable at what you are looking at and how it progresses. e.g. at day 40 of 60+, i see a ton of cloudy trichomes, but so much will pack on top of that over time... Any type of fox-tailing or new pistil growth late in bloom can make it seem like it will never be ready. So, take a gander all over the plant -- and at different depths in canopy.
if you see large portions are ripe, but canopy seemingly isn't, you are likely ready to harvest, regardless. historical knowledge with the strain helps guide, too. I am much more confident about my choices when i know it's "63 days" give or take going into it... othrwise, i second guess myself just like you the entire time, lol.
There's no exact way to know. trichomes are technically the best way, but you can get false readings based on what i explained above. So, use a mix of common sense, pistil color most importantly when possible the trichomes.