OK, thank you for the sensible post. too many children at this forum, makes it difficult to communicate properly.
surely this is similar to 23/1? your plants are bushier because you are giving them more light than on 18/6. plants stretch in the dark, due to auxin hormones. If you were to use 24/0 then the plants would stay even squatter. as you are growing clones they are already mature so you don't need to think about maturity, however as plants have better cell division (meaning actual growth) while the lights are on this means that if you use 24/0 you could flower your clones quicker, so the saving on electricity is nulled. so essentially 12/1 is not so dis-similar to any other short dark spell during veg. If you really want to keep your plants squatter and then 24/0 is the best way to go... or even 23/1. play around with 12/1 if you like it makes no difference. I cannot see the point.