Agreed, I've never seen 2o or 30 ft. plants sitting under HID or LED. Usually not even 5 feet.
Every grow parameter is different. Everything different is a new challenge in and of itself.
It's difficult to get proficient at one specific grow parameter. Mastering how to do it in all settings is really the biggest challenge IMO.
My 1/2 litre hydro pot with the Gorilla Glue #4 Auto from Linda Seeds is frosting up very nicely now, she's around day 80 and still drinking loads at high EC
NOT MINE! They're part of a cannabis group here. Super Silver Haze X OG Kush. Credit to the soil by these folks. They've got it going on. They have a website.