when your lil baby clones are trying to develop a new root system you want all your energy focused on making roots. If your light is to intense it might get light "poisened" and wilt or focus on photosynthesis instead of rooting. So like connor said prolly 2 would do the trick for cloning. Probably would be very efficient. You dont want it to intense for sure.
I have 8 in a homade bubble cloner that have been there for about 2 months. I keep the water cool and dont use nutes to keep them small until im ready to transplant them. I usualy dont leave them that long but do to some circumstances i had no choice. So it just goes to show that they will keep for a while.