Rockwool cubes

How long would you think i could go from seed in a 4" rockwool cube. I'm hoping to go 4 weeks from seed before I transfer it to the rdwc system. Wondering also what kind of watering practices would you have with rockwool

I put 4" rockwool cubes in NFT after about 4 weeks after I have topped them a few times and keep them on a fridge rack air-pruning them under a 90w UFO and as for watering, dip in water for a few seconds per day for the first week as they retain most of the water. after a few weeks as the plants get bigger you need to do it twice a day. Hope this helps.