Outlandishoutlanding, on any given flight (defined as 1st moves under own power until comes to rest at the completion of the flight) you log what happened. For example, if a 2 hr flight had .5 hr that was during a period that qualifies as night flight, then you would log 1.5 day/.5 night for that flight. You don't log the whole of the flight as day (or night) based on which period the majority was in.
Whether you are qualified for any particular portion of a flight is a different matter. If you're not qualified for type of flight you shouldn't be doing that portion of flight for which you're not qualified.