Well, using one of their (,HLG) in 3x3 isn't as hot as their larger models.
Great par tests on coco for cannabis site. They have a test set up with movable walls. That way they can replicate any size "tent" to test. They have many reviews, and do them at several different heights. This let's you see at what height it has to be above the canopy so as to not fry or stunt plants, i.e. 1100 parcenter, and what the corners (typically the lowest reading area) which will vary with height.
I was going with HlG 650 R, but looking at HLG's info, I would need almost 30 inches over canopy....this will not do with a 6 ft tent. So I would have to turn it down to get closer with corners suffering.
Some of the newest lights (expensive( are not using the most popular diodes, but are still getting correct light, using less power less heat and getting closer canopy distances for limited height tents.
When I saw their review of SP3000 in 2x4, they gave it an A+, holding 1000 par on center area, corners still at over 700. They gave this A+, the best 2x4 pattern they had seen. When they tried two SP3000 in 4x4, was even better A++! Canopy height for my setups is 18 inches.
Bubba