if the new coral came from a tank without fish, than i wouldn't worry about it. if it's at the store with fish in the tank, than that's a different story. it should in this case be qtd for 3 weeks. i don't have the setup to qt corals as you mention, so i either order corals online or straight from the bag at the lfs.
most corals can survive a period of time without the brightest of lighting also, so the qt lighting may be less of a concern than you think, depending on the coral. what type of corals are you planning to qt, and what size is the qt tank?