Careful, there's something "complicated" to understand. The amber trichomes don't turn to CBD, they turn to CBN. Which some may consider as an ersatz of CBD. If you would like a high CBD ratio, to be sleepy for instance, then you should take a strong indica, or a medical strain maybe, and harvest when the trichomes are cloudy.
Now let's say you have a hybrid, but you want to make sure to be sleepy some, then you should wait for some amber, but the "real" high of the plant gets lost. Imagine you have two strong indica, you want to compare the high they give, you should harvest both of them when they are milky, if you harvest one milky and the other one with amber, it'll make a "false" result, if you see what I mean. You might think the one with amber is more strong to sleep, better. When actually might be the other one.
Anyway, it's a complicated mess to understand. After you get that right, there's also terpenes to take in account HAHA. Good luck
