I have a 40 watt cfl light two of my clone domes. I honestly would do both ways and experiment. I have done both and have success both ways. Just remember to give them time as they are babies and take little while to develop. Spray underside of leafs. I have also cloned straight into dirt with success but prefer rockwool cubes. Also i personally hate saran wrap, its a bitch to work with. I cut a large water bottle in half and use those for my potted clones. I also think that humidity is key for those little ladies, so dome or bottle is my suggestion.
Good luck and respect