Hello, I run a sf7000 in a 4x4 tent and I start it at 35" (inches) high at 50% watching for any stretch if they stretch I drop the light to 30"... once they have two sets of real leaves (not counting the cody leaves smooth ones) I put it at 30" allow them to grow up to 25" then start increasing intensity. I keep a watt meter on the light so I know what is happening the dimmer is not accurate. Once plants grow to the light 25" I go up to 450w +-75% and maintain that until about a week or so from the switch to flower that's when I go to full power staying at 25" if they stay happy I start lowering it to between 16 n 20" watching the plants closely some won't want that much light put those in the corners where the light has less intensity if you have a short plant put it right in the middle where the light has most intensity.... these numbers are average sometimes plants don't like the light (indicas) some will want more (sativas) as you learn to read them you can play with the light power n distance you want to give the plants as much light as they will take in the beginning so when you get to flower they're not sensitive to the bright light imo higher power and more distance is better than turning down the power, they get sensitive, the sun doesn't dim and plants grow outside fine