50w/sf is a good wattage for leds. If your plants are too tall and you’re worried about penetration then build something with many diodes to provide mutiple sources of light and utilize lenses. Like 60-90 degree lenses.I'm not worried about the heat with 5 tones of mini split AC at my disposal. I would be if I was still running DE hps bulbs though.
Also I need to State I grow large trees (8-9 week veg) so penetration is a must for the canopy.