I have 8' clearance in my tents.
Lights all the way up as far as I can go.
Plants would still get into the lights. Big fat buds getting burned to a crisp. Just a 4x8 sea of giant buds.
Those lights grow big friggin plants, I don't care who you are. They are just really inefficient in the way they do it. Otherwise I'd still be using them.
If you are using electricity to heat your space anyhow, there is nothing wrong with using HID lighting. Its the only reason I haven't tossed these. No one locally wants them because it is friggin hot here most of the year.
Show me an off the shelf LED capable of veg with this spectrum:
View attachment 940
That is for Veg, and is out freaking standing at what it does. Then switch to HPS at flower, and get rid of the green and most of the blue, and you got a nice potent grow.
With double the energy use