12/12 from seed is not a particularly effective way to grow.
Cloning under 12/12 light is also not going to give you the results you are after, as the plant is already trying to decide what to make of its undifferentiated cells- root, shoot, or flower... put it under dim 24/0 light and TELL it what to do: "MAKE ROOTS!!!"
Not all strains can be effectively flowered as soon as they are rooted, either. Giving just enough veg time for the new clone to establish itself in whatever medium it will be flowered in will help reduce stress, add root mass, and ultimately, increase yield.