light distance and amount

that 600 is more likely ~300 or even ~100w in many cases.. depending on the company.. if you have a umol/s specification, use that to deduce what gets you in the ballpark for easy adjustments based on plant behaviour. Never use watts to determine anything wiht your lights.. unless comparing to another exact same # of diodes and spectrum etc etc... efficacy of parts has a wide variance... cheap COB LED off amazon are going to cost you 33% more per month to run than a better option with more photons, but costs a bit more to start. Over its life, the cheap upfront fixtures cost more. save a $100-200 now, and spend that much more per year.. plus the lower efficacy stuff loses its intensity sooner due to poor manufacturing processes and significantly more heat production per watt.

With that much draw I'd raise them to 30 for seedlings or you run the risk of light and heat stress on your little girls! Happy growing!

I'm not to sure on led lighting but my buddy keeps his about 2 1/2 feet above, but not all led's are created equal. Lights for optimal growth should be 18 to 24 hours. Cheers