I've done a lot of DWC grows and I'd keep the ppm where it's at and let the plants feed off what's left just topping up with water. Maybe some epsom salts to add some extra sulfur but they look like they may have 2 or 3 weeks before prime time.
I find most strains fatten up noticeably the last couple weeks and like to see some yellowing in the older fans at the end. Lot of green in those yet so they can steal nutes if they need it. Sulfure isn't a mobile nute so good to have a bit in the tank.
Good luck and a good harvest!