Im a living soil organic grower. With trees.depends on EC, CO2, etc.....
you can always let the plants tell you if its too much. a few hours wont hurt them but if you let it go for days could be a real setback
What did light burn look like coz mine look fine . Want more humidity i ser but thats okI set my 350R on full power at 15" AC (above canopy) and plants had light burn when I checked next day. I moved it up to 24" AC , and will keep an eye on them. Will the top leaves that got light damage turn back green, or are they permanently damaged? Guess I'll find out! first time with LED and indoor.