Darkness is necessary as light will break down your THC into CBD/CBN (and other cannabinoids). Also the reason why we store our product in dry, dark locations. Keeping that sweet, sweet THC intact.
It's best to try and dry your girls for as long as possible to keep from flash drying and hurting the taste/quality of the buds. They are still ripening after the chop, so extending your dry time as long as you can is preferable. Personally, I haven't been able to get more then 6-7 days at 50-60% RH and 70 degrees w/ good circulation. That's just me though, and the set up I currently have. You may get more or less time, pending on these environmental parameters.
No matter what you do or how long you are able to dry for, bud rot is a real threat and circulation is a very important, key factor. Keep the air moving so standing humidity doesn't become stale or pick up pathogens.
Finally, the trick I was taught to tell when they're fully dry, is to snap a stem everyday or twice a day. If it has an audible "snap" but doesn't break, they're done. If you bed and they are still rubbery without the snap, needs more time
Hope this helped man. Drying is yet another learning curve and one I'm working on myself. Good luck and happy grows this week 👍