yes you should. the reason behind this is that the darkness helps the buds to ripen up a bit more before chopping and getting that nice harvest.
although some say it does nothing and some say it helps, in the end it is your choice, and what is two days of darkness just to complete your grow as you have already come this far. so congratulations on the up coming harvest you did a great job. if you do decide to do the dark ness you should give them just water right before you close her off. this way the roots stay moist
during this time. you are going to be one happy grower thats for sure.
No don’t water , let them in the 48h of darkness with the pot quite dry, they will not drink pratically nothing in that time .
And yes you should, it’s very useful , it will improve the quality of your crop ✌️🏽