Your space isn't too small for that light. You may need to induce flowering a little earlier than you would with a higher ceiling (approximately 1 1/2" or so), or you'll need to become very familiar with gradual training methods. Seeing as how you have plenty more horizontal space, LST might be a pretty good option. Either that, or topping may be in order. Though, I don't like to prune anything off of my tops...only leaves/stems that aren't receiving enough light & won't produce good buds. Then again, I have much more vertical space to work with...and I also supplement adequate side-lighting. Be especially careful if you start growing any sativa-dominants, though. They like to grow taller, as opposed to wider.