Going to be used with 310xt, so the unit mount needs to be 90deg rotated and so won't work with the Zipp mount. Looks like you can do that with the Superstar aerobar mount though, what with the bolt in the centre, a lot like the official Garmin mount.
31.6 down to 22.2 is going to need a lot of shimmage. Just buy the Zipp TT mount.