Reeflo barracuda

I have a Reeflo barracude return pump and I want to be energy-wise on how many watts it runs.



I've been told the more the GPH flowrate is lowered, the less watts its consuming. Is this true?



If I were to reduce its flow, at which ball valve should I constrict flow?



I have a ball valve right before where it inputs water into the barracuda.



I have a ball valve right after the output of the barracuda.



I have ball valves right where the returns go into the tank.



Where do I constrict?