wanted to add... i've done the "dim and get closer" option... it is not as good as simply raising light at full blast. Immersion from all angles increases -> only good things happen if not "too much", which the added height would ameliorate. All i asw on clones was more leaf and smaller buds when trying to get lights closer and save a few watts. (similar light structure - diy though)
Also, when you start dimming to 50% or more you end up changing your light spectrum in some way shape or form.. consistency of what is produced is not the same in all cases. The further you dim, the more variations can occur.
I like saving watts, but not at expense of what is produced. dimming for seedlings or sensitive young plants is fine... but once you are at this stage... you want them immersed in photons from all angles (leading to top of a leaf... not the bottom of course)