well.. i didnt use rapid rooter plugs, but i asume it would take roughly the same time.. my took about 2-4 days to go from put in plugs to actually sprouts. as for nuts by the 2nd set of leaves? i don't know how many plants you have but lets say take a 32oz bottle. fill it with water, and add mybe 5 to 10 drops of nutes. that will make a really weak ass solution but it will give your plants just enough. I would start watering with this after you see the first set of leaves. then when they get to the 2nd set, you can double the nutes and by the start of the 3rd i asume you can put them in your system. Im not an expert but that is how i did mine and they are doing great. good luck