Maybe I’m oversimplifying, but in my experience the most effective reward for extra work is extra time. If somebody that works for me has to work a weekend to hit some objective, I thank them and tell them to take 2 days off the following week.

A parallel comment mentioned burnout, and I think this is the only viable way to enable above-and-beyond surges while minimizing burnout risk: as a business, you have to decide that a surge doesn’t mean you’re getting extra time from people, you’re borrowing time forward against future days.