I have a 4 bike hanging rack that’s probably 15 years old. Dates back to when I had a 4 bike family. I subscribe to the buy once, cry once philosophy so I’d recommend a 4 bike rack for you. Shop all rack styles because the 4 bike hanging type can be a hassle to get all the bikes on and off, depending on bike frame designs. Definitely don’t leave bikes on a rack overnight in a parking lot. There isn’t a lock strong enough.