I agree w/ lizbud, you should try to get one or several of the rescues to help with this.

Does the warehouse have an office or any room? Working them in to one room will make things lots easier. Then I would suggest following TNR procedures, for trapping feral cats. The difference being, if these dogs were ever pets, ever handled, once caught they will calm right down.

Don't worry about getting them OUT of the traps, let the rescue or a vet do that. Then the dogs will in a small exam room, easier to handle.

I also suggest getting 5 traps, but do work with someone familiar with this sort of thing.