I think DK3 is better built for this sort of thing.
Time-wise, I like the Kong Klub 5-minute challenge, but something a little longer might be better in this scenario...15 minutes? 20? What does 31 stages of Galaga take? 15 minutes?
Score/distance-wise, if you're not going to make a dedicated tournament romset, then something like "End of Level 5" might work. That would keep games under 35 minutes or so and gets you through one cycle of every difficulty of every board type. If you make a dedicated romset, then anything goes. Fixed RNG, fixed start and end points, fixed time limit. You could do something like "Start at Level 5 and give each player 15 minutes, with the same RNG." But dedicated romsets would be a pain to implement