My European races have recently only been two days and one night so n9 sleep. Did UTMB with no sleep though, altho perhaps with some sleep I would have been faster and had fewer stomach issues.
On last year’s Hardmoors 200 miler I had a flexible plan and changed it at 3.3am of the second night when I stopped, slept and ate for about 2 hours total. It meant that rpthose on the 100 miler started about 3 hours beh8nd me so I had people near me for much of second day and night. I was also keen to sleep in dark and not waste daylight . I suspect a 20-30 min doze on the second night migh5 have helped as I kept falling asleep on my feet but I wa with another runner and did not want to lose that pairing of moral support and help with nav