Hello 30 inch's for 522 umol/m2s should be fine for veg. 24 is 760 in the middle but most aim for around 600 for veg. For flower you want up to 1000, above that you want co2. 18 inchs is 1036 umol/m2s in the center. For unrooted clones I would go even further then 30 inch's, once they are rooted...