I've been hunting coyotes and fox for a very long time. I don't think there is any one sound that is best for coyotes. Different times of the year and just different days make a difference what they will come too.
First thing is locating the coyotes, Use a siren call to do that.
Right now the pup whine is working and soon a fawn in distress works well. A hurt Rabbit works well many a time.
They have came to chicken fight sounds and even wood pecker sounds.
Al