To see who really covers all difficulties I would suggest:
A) add up all 3 ranks, who has the lowest score wins, or …
B) add up points from all difficulties, highest score win.
For example (makes sense when event over of course):
So at the moment my A) score is 871 and B) … too early to count anyway
What do you think, @zephyr1 and would love to compare here when event is over!? And maybe a loot category for that, SG?