Looks great. Nice grow.
Regarding your watering schedule. With Rockwool/hydro you want to water as much as they can handle. That's kind of the whole idea around hydro. Even though it doesn't need to be watered, you gain extra growth and yield by watering 3 or 4 times a day for 10-15min per. Yes you can get away with watering less, but your yields and veg growth will increase with a standard hydro watering schedule.
I know it sounds odd, it did to me too when I switched from soil to hydro.
Water as much as you can without hurting the plant. RW breathes well. During my veg period of 18/6 lighting, I was was watering 6x a day.