Depends on where and how long the overnight is.
In my younger days overnights were typically races on Lake Ontario and the crew was poorly organized. Most of the crew would be ramped up, have a few beers and then fall asleep, leaving a few others to tend to the boat for the rest of the night. I learned to hate overnights and stopped doing them.
On our trip south in '21-22 we did several overnight run, including one 54 hour sail. The longer sail was easier than the shorter overnights because it is easier to get into a rhythm and your body begins to adjust to frequent shorter sleep times. On shorter runs, less than 24 hours, the body just doesn't adjust to a new sleep schedule.
We use a flexible schedule based on a 4 hour shift. My wife tends to go to bed earlier than I do, so she slept first. We don't hold to a hard and fast 4 hours, we sleep until we naturally wake up or until the on watch really needs to get some rests. So some shifts are short, maybe 3 hours some are longer maybe 5 hours.
When on shift I set my watch (Apple Watch) with a 20 minute timer. Every 20 minutes I stand up survey the horizon, check the AIS, and check the Radar. The timer automatically resets effectively putting me on a 15 minute rest/scan rotation. The horizon is about 3 miles out, in 15 minutes my boat will only travel about 1.5 to 2 miles, so there is a good margin.
Conserving energy is important. We found on our longest crossing (54 hours Abacos to Charleston, SC) having brownies really helped. I allowed myself 2 brownies per watch.
