Daytime sleep, done properly
Blackout curtains, cool room, phone in another room, consistent sleep window. Six hours of good sleep beats eight hours of interrupted sleep.
Caffeine strategy
One coffee at shift start, one at 02:00, none after 04:00. Total under 400mg. Front-loading buys you two good hours and costs you six bad ones.
The alertness kit
Chewing gum (sustained low-level jaw movement fights microsleeps), a hand grip trainer at your desk, a five-minute walk every 60 minutes if the post permits.