Baddies nothing. That's a large number of people to coordinate, and unless they're all used to running together they're likely to be slightly out of synchronization to start with. Oh sure, if they're all good than with a little practice they can get everyone on the same boat, and get well synchronized. However, you're probably not going to get 24 people to do 2-3 WoD runs back to back, just to see what the lowest Speed-run time is. I guess I was envisioning something a little less formal, ie, everyone on their main classes, with running with the people they're used with. Getting a group of 24 people together like that seems far more realistic than what other people are suggesting.
I mean, considering how much time it takes to get 24 people together, when roughly a 3rd are shoe-horned into an alt class, and all that.