Diablo is a powerful light and hang recommendations are guides only. It’s a balancing act between height and power.
This light has lots power
within the closed space of a tent and should powered to what the plants can tolerate. I have used dimmer power and reduced height to canopy with less powerful HLG lights . But these , you gotta be a little less on the throttle. I agree , I can’t see that rig just nuking plants at full 100%.
I run the Blackbird at 22” @ 800-840 umoles canopy for my 3x3. The dimmer is actually only on the 3rd notch. I look for at least lateral leaf spread to tell me where to stop. 900 umole would be the most I feel comfortable with mine. Even tho I have power to spare , I don’t look to ever run 100%.
Even tho I have plenty of gas at the pedal doesn’t mean I need to air-fry them.
My 3x3 “ numbers “ I shoot for is 770-880 ( 900 max )