Hello Catsmeow, your girls are looking great 👍
I understand your looking for a way to see when your ready to harvest.
Let me say it like this, there are more ways to see if your almost ready.
There is just one way to be 100% sure when your almost done and thats tio check your trichomes with an magnifier at least 40x
There are 3 stages of trichomes.
the first stage is when the trichomes are clear one and that means its still in development and its early to harvest.
the second stage is when the trichomes turn cloudy /milky, thats the perfect time to harvest. make sure the atleast 90% is milky when harvest.
The last stage is amber colored trichomes, its means your trichomes are degrading and you get less tasty bud bud more narcotic effect and a bit harsh on the throath when smoked.
If its just a few procent that turns amber its not that big of a deal, but try not to let too much turn amber if possible.
Hope this was an helpfull answer my friend, if so like the answer 😀
Keep on growing, Peace 👍