Have to agree with everyone. You can do clones with very little lighting, i have had clones successfully root in the window in the winter months, ie less than 12/12.
I have done them in 12/12 and instantly put them into flower... The only problem i noticed was lack of root growth during the flower cycle... You want to establish a health root base before you begin flowering... I would say 18/6 til rooted and than after transplant continue with 18/6 for one week before switch to 12/12 will help establish healthy roots... OR possibly although i have never tried you could start hitting it with low doses of kangaroots after it displays roots. The problem i encountered was that the roots did not grow as fast as the plants needed them to in flower resulting in some nasty looking yet still fulfilling buds.
As for clones I usually cut on top of the 3rd or 4 node set at a 45... Than from there either bubble cloner, cloning gel/powder and plug, or my favorite, just stick it in a cup of water.