Your DLI is maxed out for sure, maybe a little high, without CO2 the max is 40-45. But some varieties do fine with that. Watch for foxtailing. Brown tips are not something to worry about, almost everyone gets these at one time or another, just a little heavy on the nutrients somewhere along the line. Just watch that it doesn’t damage more of the leaf. You’re pushing the limits I’d say. Just make sure the buds stay nice and tight. Every plant can surprise you.