I don't dare give fertilizer nutrients to the...

I would suggest backing your lights off to 24-30". You should go by the manufacturers recommendations. Are they drawing a true 1000 watts for both of them or is the true wattage draw more like 300 watts each. If the light is too strong/intense you can actually stunt the seedling/plants. Using a PPF/PAR meter is the best way to know how intense your lights are at different distances if not your just guessing.https://horticulturelightinggroup.com/blogs/news/horticulture-metrics-par-ppf-ppfd-dli I would start high then lower them a few inch's every 4-5 days especially if you see them stretching for the light. I'm not going to B.S. you I have no experience growing in rock wool so I have included a link. https://www.alchimiaweb.com/blogen/grow-cannabis-rockwool/ I will recommend two things for you 1st is to add a cool mist humidifier to the grow space your humidity needs to be in the 65-70% range to avoid an issue with LVPD ( leaf vapor pressure deficit ) until your plants have grown a good sized root system this has to do with plant transpiration which allows nutrients to properly absorbed through the root system. The reason your seedlings leaves are curled is either light stress or their trying to conserve moisture do to the lack of humidity. http://www.just4growers.com/stream/temperature-humidity-and-c02/vapor-pressure-deficit-the-hidden-force-on-your-plants.aspx 2nd try to keep the ph of your water/feed solutions 5.6-6.2 ph for hydro. There are way too many opinions on ph for hydro but it's shown that the best nutrient absorbtion is in that ph range. You can also check out my current grows there is some information in week 2 about PAR and LVPD👍