Phil,
I started off with just my ignition key on the quickconnect but my main ring was growing so fast that I decided to keep all my bike keys on one and my house/cage keys on the other. I also have my helmet lock right below my ignition so they have something to rest on and it keeps them from flapping too much. I haven't seen any scrapes on the frame yet. I could always make a wrap of electrical tape where they have the possibility of touching the frame to keep them from scratching it.
