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.
@spotter
Look good! What size can the shims reduce the clamp down to? Their site doesn't specify and I'm hoping to fit on to TT extensions...