There are so many different types of lights out there by how you are describing them they’re the older style leds. I have a couple 600 blurple lights that can do one plant each but both together do much better so I’m guessing completely that your 1200 is the way to go, possibly both of them.
As for distance I don’t want to give any numbers not knowing more because I’d hate to hurt your plant
Yes the wattage powers your lights but with today’s LED diodes what you need to look for is PPE… Photosynthetic Photon Efficacy(PPE) refers to how efficient a horticulture lighting system is at converting electrical energy into photons of PAR. Many horticulture lighting manufacturers use total electrical watts or watts per square foot as a metric to describe light intensity. However, these metrics really don’t tell you anything since watts are a measurement describing electrical input, not light output. If the PPF of the light is known along with the input wattage, you can calculate how efficient a horticulture lighting system is at converting electrical energy into PAR. As a reminder, the unit for PPF is μmol/s, and the unit to measure watts is Joule per second (J/s), therefore, the seconds in the numerator and denominator cancel out, and the unit becomes µmol/J. The higher this number is, the more efficient a lighting system is at converting electrical energy into photons of PAR.
Then take a look at the lighting map for how well your light footprint delivers the PPFD at various distances from your canopy.
The light output PPF of HPF4000 is 1300µmol/s,its actual power is 480 watts,so PPE(Efficiency)=1300/480=2.708333µmol/j
In order to invest in the proper horticulture lighting system to meet your cultivation and business goals, you need to know the PPF, PPFD, and photon efficiency to make informed purchasing decisions. However, these three metrics should not be used as sole variables to base a purchasing decisions.
You also need to consider other factors before purchasing a light, such as heat dissipation, energy efficiency, light lifespan, waterproof, etc.