Preety much that ^^^ My plant is just starting to show a couple pistils under 20/4 lighting. Now I'm about to start flowering is a long dark period needed if is showing pre flowers?
It isnt required to do 24 hours of dark before switching regardless. Some people will say they do, some dont. I just went to straight 12/12 and mine showed a male in the first week, the rest were females and showed in the second week.
The idea is that the darkness (32-36hrz) is the recommended, shocks the plants light cycle to accelerate the crossover from Veg to flower. If you factor it in to your regime it doesn't add time, when your flower room is just turning on put your veg in the dark and then put it with them once the lights turn off. I add a good flush prior so when it comes out it is clean, thirsty and ready to grow. The whole theory makes a little sense...
I'm sure it won't hurt to do this but I don't think its really needed personally. I've always just went straight into 12/12 lighting with no problem whatsoever. Good luck
I do a 24 hour dark to start. I can't tell if it helps but I do it anyway. I think 36-48hr is too much, that may stress the plant.