I wasn't aware of this Topeak mounting/release device. This is the type of item every shop should have one on hand. It's what I call a "getting out of jail" device. It can make all the difference in solving a customer's problems quickly and without much cost.

What I note is that it places the cage somewhat higher/lower on the tube with it's offset, from the tube bosses. cage mounts. I have done much of this same relocating using hardware store Al 1/2" x 1/8" strip. Here's a shot of our tandem, after some braze ons changes and respray, that show the strips also angling the cages for easier access. Andy