When to use ultimates in Junkenstein's Revenge?

From the perspective of trying to get high scores on the event: Use ults often.

Given you have enough enemies to kill, you can build ults again fairly quickly. Even more quickly if you let players who need to build ult do all the killing.

By my estimates:

• Ana takes 40-60 seconds to charge ult
• Mccree takes 15-25 seconds to charge ult
• Soldier takes 25-35 seconds to charge ult
• Hanzo takes 10-30 seconds to charge ult (depends on amount of headshots/misses)

You can use these at about any time as long as you have them for the necessary boss fights. For actual timings:

Boss Timings

• 4:41 Reaper: Deadeye + Nano Boost
• 2:45 Roadhog: Deadeye + Nano Boost, Dragonstrike, Tactical visor
• 1:45 Junkenstein: Dragonstrike
• 1:35 Reaper: Deadeye + Nano Boost (should clean up junkenstein as well)
• 0:30 Reaper: Deadeye (DO NOT Nano Boost)
• 0:00 Triple Threat:
  • Dragonstrike on as many as you can
  • Deadeye + Nano Boost,
  • Tactical Visor on smaller bosses as necessary, but mainly Roadhog

The shock tires count as Elite kills. I'm not sure if they affect score, but correlationally I've seen ult combos used to kill them leading to higher scores. Anyone's ult will do, but keep in mind the boss timings thereafter.

Shock tire timings

• 5:50 Right: Anyone
  • Nano boosted Soldier is fun here since there is over a minute before the next boss.
• 5:32 Left: Hanzo Dragonstrike
  • Fire from the bottom of the staircase clears many zomnics and the tire. Usually grants POTG.
• 3:53 Middle: Soldier or McCree
  • Plenty of time before next boss, but I prefer Soldier. Nano boost can be used here as well.
• 3:38 Left: Again, Hanzo Dragonstrike
• 3:22 Right: McCree or Solider.
  • McCree preferred for combo-kill potential (though he needs his ult again in about 30s!)
• 2:22 Right: Hanzo or McCree.
  • This is right after/during Roadhog, so Soldier usually is on CD. Hanzo or McCree are most likely to have ult again.
• 0:49 Left + Right: Hanzo and/or Soldier. Optionally Nano Boost.
  • Hanzo can actually ult from left-to-right and get the right side, while scatter shotting left side tire for easy POTG.
  • McCree should not be used because of the upcoming Reaper fight.

Other than that, all three offensive ults can be spammed at will between bosses. I've found that a large wave of zomnics spawns at every minute mark, so firing a Dragonstrike around then can work wonders.

As long as you don't take door damage or deaths, ult spam/combos can net you a 23-25k score easily.