Congrats
The idea is changing the plant environment as gradually and slowly as you can.
This means that it basically depends on the humidity you have normally in that room, assuming the temperature inside and outside the bag is the same (it will be, if the plant does not have heating below). You will have inside of the bag easily a 80-90% humidity, so the adaptation time should be as long as the difference between that and the outside humidity.
If you have a thermo-hygrometer you can find out in a second. I can get one in the dollar store for around 10$, so it might be a good thing to have. Then, you have to options:
- Removing the bag for an hour once a day for a few days, then twice a day (or once two hours) and so on. Keeping the process as long as it takes, but I would extend it for at least a month. And if you have to leave for more than a day, just leave the bag on.
- Making a little hole a day in the bag.
By doing this, you can largely prevent the brown ridges in leaves. They are not fatal, but they take leaf space and are prone to expand.
In any case, take your time, make sure the stress is progressive. Keep in mind, though, that if the overall change of humidity is important, you might need to give her a light misting a couple times a day once the plant is spending most of the day out. And if the leaves (particularly the new ones sprouting) appear more small and sturdy, don't worry. It's normal, the plant slowly adapts her morphology to differences in the atmosphere.
"The Menu is Not The Meal." - Alan Watts