That's your answer right there. The space between the hooks should be the width of your handlebars. I've got mine lined up, handlebar-to-handlebar, with a second row that let's me use the space in between. I tried hanging alternate bikes from the rear wheel, but that's awkward to hang or take down. The second row is also tricky, since it needs to squeeze between two sets of handlebars, so you might want to leave an extra couple of inches if you plan to do that.

BTW, the RubberMaid FastTrack system lets you move the hooks.



If you're just screwing hooks into the wall, you'll either need an additional board to screw into or you'll be limited by where the studs are.