Hey mate.
So, for your 1st grow, keep it simple.
So, you want all your plant more or less done at the same time.
So, its a trade of with higher cloudy trichomes + more ambers and lower on the bottom. (Generally this can be combatted by lowering your light % at ripening to not push the plant to hard, making it finish more evenly)
As for the 48 dark rest, mep, I've harvested over 150 phenos, and tried every way trying, I've tested half harvested, half dark rested and the other half harvested after 2-3 hrs of light been off (as when the plant has been In the dark for 2hrs the photosynthesis actually completely stops and in theory the plant is in the same state as it would be in 48hrs as it would be after 2-3 hrs of rest. I would advise focusing more on your timing of harvest and your drying room. So, after the plants have stopped photosynthesis (photochrome affect), you want to cut the plant in your dying dark room. So, as soon as you turn your light off, place your plant in your dark room, or tent if you're using, wait the few hours, and then in the dark, or very low lux environment. Then you can cut from the stem and hang upside down. Some growers wet trim. But, if the bud dries to fast. You'll end up with bushwhack weed (smelling of hay). So the longer drying 10-14+ days the better. And as the days progress you can start removing the main fan leaves allowing air in more, and as it continues to dry. You can then break it down into sections, and rehang and in a few days after that. You can start trimming the sugar leaves (note: it's best to do this before fully drying as if the sugars fully dry, they'll be harder to trim the end product.
Drying conditions
Again, this can vary depending on growers and ambient environment
Tempature: 17-20c keeping between these to ensure your weed doesn't dry to quick
RH (HUMIDITY) 55-60% Some ppl like a lower RH as it gives more kief separation if you want to do hash, but typically, sticking within these ranges shouldn't cause any issues.
Don't
Airflow: you don't want direct air blowing on your bud, but good air circulation in your drying room. Or if your use your tent just know on your exhaust and keep it low. (If you've the consistent conditions
If you any insight or help in anything explained feel free to reach out myself or the persons answer you find most helpful.
Good