First, looks awesome. it's happy, it;s praying, you have good light penetration throughout plant.
if vertical growth stopped but still bushed out, it could be pot size. if in coco -- but 2.4 gallon pot size is great for an auto, but a photo with alonger vege period may stop growing taller at some point in one.
this is how i maintain my donor plant's sizes. they are in about 1/2 gallon of coco. hydro requires less substrate than soil, if comparing directly, fyi, because i can provide more nutes per volume per second etc.. anyway, my donors don't grow beyind 18-24" tall because of this, less intense light, and a bit less nutes. 1:1 with pH'd irrigation and up it at sign of deficiency occasionally or a week leading up to a clone taken.