@Rugar89 That's a great question!
When it comes to the distance you should go by the manufacturer first and then if not @Niala did a chart for us
I will paste it here:
Here's a chart for LED lights, it's for equivalent watt, so if your LED light is 300W follow the chart for it, it's not made for actual or real draw and it's an approximation, that clarify, here it is :
120 W to 180W ~1.5 feet
180W to 300W ~2.0 feet
300W to 600W ~2.5 feet
600W to 1200W ~3.0 feet
1200W to 2000W ~3.5 feet
Hoping that's helping as many as fellow growers possible
From Al! @Niala
If Al stops by he can answer why we go by the equivalent and not the actual.