Replying to Mounting scratch bc's

ok first off i searched for threads that might answer my question, but didnt find any at all. I have some 06 185 scratcjh bc's that i need to mount. i weight 175 and im about 6' tall or so. im using these as pow/all mtn/charging ski. i also wanna be able to land switch into pow and ski pow switch some. where should i mount these, i was thinking maybe like 2 or 3cm's back from true center?im not sure what that is from reccomended, but any input would be great, thanks.