thats going to depend entirely on the density and structure of the flower lol. I tend to dry closer to 50% for larger/denser buds with a tighter structure. If i get looser or airier, or less resinous buds ill dry closer to 60%
Generally i try to make it take about 10 days to dry the flower. But accept anything between 7-14 with satisfaction usually. Usually im drying at a cool room temperature of 65-68f, with RH of 50-55%, but im also not a stickler for getting the details perfect. If its a bit warm and dry ill hang the branches closer together or leave more fan leaves on em, or lower air circulation, and vice versa.
Still glad i dont rely on anything wifi or digital to help run my grow

In a similar way, to when i climb in a work truck, and notice it has hand-crank windows... Much preferred. I even still prefer mech timers to digital. When they break, im rarely not able to fix them either lol. Same with LED drivers. I tend to buy cheap panels because i have stockpiles of everything id ever need to repair a driver, hell i could make one from scratch in a pinch with a linear supply if need be.
I measure temperature and humidity with my skin lol. If i dont break a sweat working in there, its fine. The cool thing about being one of the few species of organism outside plants and horses that transpires moisture through their skin, is that you can develop an incredibly accurate sense of temperature and humidity differentials both if you want to. You just need a frame of standard reference, kinda like training yourself to have perfect pitch simply by memorizing a single note, like C or B or something, because of the consistent intervals between the rest of the notes you can accurate infer all of them based on that single, consistent, memorized reference point.
Fun loosely relevant fact:
You can actually train yourself to sense magnetic north from any location accurately without needing stars or the sun too. You just have to memorize the particular sensation of a particular reference point, and it works because of the iron content of your blood. It's actually part of Navy Seal training so you can navigate even if you lose your instruments during a deployment.