Well if you top them or train them you can grow some good sized plants and only have them 2-2.5 ft high add on to that 10inch for pots and your space between light and plant and a filter up top, it can be done, probably a little tight for head room. But not to much bother, stick with indicas if you do only have 5ft height.
My mate has a 3x3, that's 5ft9 tall. he grows vertically though but has room for 2-3 levels of plants in that height, 3 shelves one above the other.
Anyway, take your time, don't rush into buying, have a good look at what is available. You've made a big leap and bought an awesome light , the main thing is you get the most out of it and enjoy the journey.