all my clones are under a single warm white 40 watt florescent, and a cool white 20 watt florescent. Intense light is never recommended from what i've heard!!! one or two floros is PLENTY for clones . i try to keep the base of the clone dome warm, and its best to keep the clones in a highly humid environment its why the dome is useful. I personally have experienced nearly 100% success rate. i use cloning gel, and rockwool cubes, and have successfully rooted more than 150 clones with this method
i give my clones 24 hours of light, once they are fully rooted (1-2 weeks) they can be put directly into 12/12 flowering or you can veg them with 18/6 or 24 hours for a few weeks depending on your grow method.