Just checked my logbook. My five-hour night thing nine years ago consisted of:
* Trip 1 - Dual night famil/navex/circuits (7 landings) - 1:55
* Trip 2 - Dual night circuits (2 landings) - 0:25
* Trip 3 - Solo night circuits (4 landings) - 0:50
* Trip 4 - Dual night navex (1 landing) - 1:00
* Trip 5 - Solo night navex (1 landing) - 0:50
Trip 1 done on day 1, trips 2-5 done the following evening. Total five hours in two days, job done! Just use it for getting back a bit late if necessary (puts less pressure on getting back and allowing time for a divert too), and worth it for that alone. I still make an effort to keep night current now (i.e. able to carry pax), just to cover the return late thing.
Andy