The Shiv Disc comes with a 0mm offset seatpost.  While the 0mm post appears to have a setback, it is inline with the seattube.  A +25mm forward offset post is available, 28119-3605.

A rubber grommet, S204900001, covers the seatpost wedge, S194700004.

Saddle clamps are the single bolt design, 2812-9050.