I don't think light overkill exists.
I think as a beginner I can liken this hobby to owning a car.
Most people just own one a drive it and beat on a Car.
but some people love the car, feed it expensive oil, by accessories for it.
Some people like having a race car.
I like pushing to the limits of my equipment and Nutes to TRY and get the best possible yield.
I am flowering my first plant, day 26 from time flip, the first 7 was the stretch then bud formation started.
I dont see two side by side hoods with 600 watts each overkill, it's only 200 more watts than your 1000.
I like redundancy, if one light burns out the other one will stay lit.
i would also have the ability to flower with HPS and Metal Halide at the same time, I have read studies saying this produces really good Bud.
I also like the ability to load the light spectrum with my red and blue T5 CFLs. As supplemental side lighting.
Some people drive a Hyundai some drive a Jag then you have people like me who are into Big block 70's Muscle Cars with tons of horse power.
Woa a 4x4 with 2x 600's? I am a 100% noob when it comes to how much light is needed but isn't that overkill? I have a 5x5 with a 1000 watt HPS in it. Perhaps I am not running enough light? Sorry for the myriad of questions lol.
Also that is exactly what I did with my old 2x4 tent. It is now my drying room that I can control the humidity and temp perfectly in.