I think too many inexperienced trappers try to rely too heavily on the "lure" aspect of what they are trying to accomplish in catching more fur. The object of course as with anything is to produce the most fur with the least amount of expense and frustration. In considering what lure to use I think one needs to separate the two types of trappers that go after coyotes:
1. the fur trapper
2. the damage control trapper
Its hard to debate coyote trapping when we combine these two schools of thought. The fur trapper is simply trying to catch as many coyotes as he/she can. Catch the easy and dumbs and move on to the next farm. These trappers need not worry so much about the gambit of lures: call, food, curious, gland, etc.... If you are trapping for fur, find a good bait and get to it. Spend your time and efforts learning where the coyotes are and will be. Learn how to make good sets. Get ground to trap and you will be successful. No matter how "good" a lure is... you won't catch coyotes with poorly located sets or poorly constructed sets, period. There is no "magic" lure.
Now, if you are doing damage control and you need to catch each and every coyote or that one shy biotch coyote that is like a ghost.... now we can begin to break down the science of lurology.... and I don't have enough experience in this area to even begin to discuss this topic. If you are not a specialist in wildlife damage control I would not even recommend exploring lurology because you will eat up countless hours on the internet and just end up scratching your head this winter...LOL
I guess I really rambled and didn't even answer this question... so I will do that
my favorite coyote lure: personally collected, blood red meat fed piss from a penned up red fox... the nasty junk that settles at the bottom of the bucket....
my favorite coyote bait: RK predator plus which is the Nelson formula