The more light, the better. If you have the 128 now, use it. You dont necessarily have to ADD lights when you flower. You can simply use all you have now, and switch to 12/12 for flower. The more your plant grows now, the more bud youll get when you flower. The amount your plant grows now depends heavily upon the amount of light it recieves.48 watt to start with then 128 watt when flowering time rolls around eh?