1st round: solve 20 basic tsumego problem. pick some winner based on their correct answer & their time duration
2nd round: more difficult tsumego problems
…
final: battle of two person solving high level tsumego problems.

During one french summer camp we did this during the lunch. Each day was a different categorie (tsumego, joseki, fuseki, tesuji…). A bunch of them to solve quickly on a paper sheet.

Maybe different categories for designing tsumego targeting different levels? so what might win a category targeting ddks, would be very different from what would be in contention targeting mid-dans

I’ve heard of a chess tactics tournament that worked, if I recall correctly, by giving the contestants a bunch of problems to solve, like 1000 (maybe there was a time limit and you tried to get through as many as possible?). Then there was a break of a month or two. Then there was a second round where you faced the exact same set of problems. 1 point for each correctly solved problem, so max 2 points per problem if you got it right both rounds. It tested a combination of solving skills and recall of previously seen patterns

EDIT: note that you did not get to review the problems during the break, you just had to rely on what you remembered from the first round