If you already see roots, go ahead and treat the cuttings as if they were seedlings, watching to see if they show signs of being too dry and warm- droop, wilt, or upcurled leaf edges. I like to keep just-rooted cuttings out of bright intense light until they have almost doubled in size from then they were cut off the mother. So a cutting that shows ~3" above the plug when I first insert it, I'd want to see at least 2 new sets of leaves unfolding, or a couple inches vert growth- either one- before introducing it to the HIDs. That's also a good time to introduce a light dosage of fertilizer. I use a weak foliar mist of the GH Micro, which has just a bit of N in it too.