To increase hydration and get a more open crumb it is best to add more water just a little bit at a time. The technical term for this is what the French call called Bassinage. We don’t have an English direct translation for, but it means water that is worked into the dough in small increments during the bulk fermentation.
It is a very traditional technique, but what is really important to remember is that the ” eau de bassinage” ( the water) is removed from the total water in the formula.
So if you have a total of 800g of water in the formula with 50g bassinage then you will mix 750g of the water in initially with the flour then add the 50g in gradually at the later stage during the bulk fermentation stage.