You probably have a standard setback seatpost already, so just stick with that. Use a torque wrench. Be sure the collar for the seatpost is the right size and that the post you buy is the right size for the frame (go with standard, standard, standard---no aero seatposts).

Don't attach anything heavy to the seatpost (like racks).

Otherwise, the only thing to worry about with carbon is that very heavy riders probably shouldn't use carbon.