I have a pair that were originally my all mountain skis. This season I used them almost entirely for park, and remounted from -2 to center. If your not doing park only then -2 is fine, I personally would have gone -1 because that difference center didn't feel too different on groomers
a passionate skier looking for new and lucrative ways to acquire gnar points
Center or 1 to 2 back. Honestly you wouldn't notice much of a difference even if you did remount them to see. If you get them centered mounted and your feet grow a little bit, but only enough to require sliding the heel-pieces back, not fully remounting them, then they will be a little bit behind center anyways. If you put them back from center and this happens they are going to be further back.
Im sure if you try it it will all make sense once ur in the air - Blow.Jib