So, that worked out, at least for the moment. The kit of course tells you to screw into a ceiling stud. But it turns out that finding a ceiling stud, at least in my old Miami Beach apartment, is not as easy as advertised. Even the stud finder I borrowed (which worked great on the wall) gave all sorts of crazy readings, and was just generally unreliable. After some hunting around, I decided that toggle bolts might be worth a shot.
They work! You need to pre-drill big-ass (3/8”) holes, and be careful not to screw up the installation (i.e. screwing with the drill in counter-clockwise mode, which will basically ruin one of your toggle bolts in about .5 seconds), but this setup has 4 bolts holding a 30 lb. bike, and seems to be pretty effective.