Hey Amber, in a UC system since it is on the floor you don't need more ceiling, as much as you need more square footage to spread them out. Lose the horizontal reflectors and drop verts. That will give you an extra few feet of vertical canopy.
Then you can add a wire grid ceiling and start dropping yo yos! You can also hang the cages from the ceiling and then you can peek the roots if you need to.
Those plants came out tits, but you could get them a lot bigger still and double your yield I bet with another week or two of veg. If it were me in a horizontal grow (keeping your exising setup) I would find a really strong stemmed upright strain that can almost hold it's own. Then let them grow in to each other, and remove all the lowers. That would give you a big blanket of flowers and increase your yield probably 25-30%. If all the big buds are close to each other they have a tendency to support each other as well. You could even lower your existing cages 6" or so (break out the grinder!) and zip tie a flat 4'x4' wire mesh to the top (horizontal plane), anticipating that the flowers will stretch through that and then you have all the support you would need. It would look like a giant scrog, but with 9 big plants.
I have been thinking about dropping 3 plants from my room so I can get some more space in between. With the right strain, you can easily hit 3lbrs on 5 ft centers.
I would only have 6 plants then, but if I averaged 3/ I wouldn't complain.