So 1 foot 9 inches from the bottom of the growing space to the top, so 21 inches, it's definitely doable as a ScrOG and only one plant or maybe two (it'll be hard to get to the growth near the back), you can small rubbermaid like container that is only 6" high but much wider than most pots, that'll save a little vertical space, then put the screen 8" above the pot, so 14" above the bottom of the grow space. You'll have to use CFLs and figure out how you want to mount them or fix them so that you can raise/lower them.