Growers using 600W

[Sensi Super Skunk]

I have a sunsystem 600W/Horti

The thing gets hot but if I use the hand/minute method I might be able to get the light 1 1/2 feet away from the plants. First, those of you wit 600 or 1000w systems, what is the effective range you use?

Second, is there a point where if I am 1 foot away or 3 feet away, it makes no diffrence?

thanks

Just invest in an air-cooled hood.