if two of them are already a foot and the smallest is eight inches, then i would go ahead and throw it into 12/12 now. i like to put mine in flowering stage around 8-12 inches as any more taller than that will give you too big of a plant as it grows way MORE during the flowering stage. you wattage of lights seem good to me, but you have to be more specific. what kind of 150w grow bulbs are those? what color spectrum?