if coyotes are coming up to the set and not committing on a regular basis without, they are attracted to and seeing your sets. Don't worry too much if any about lures or baits- if they are seeing your sets, they are. Beaver down a hole will certainly attract canines enough to work the set. A good lure will help, but don't get into the mindset that there is any magic lure- every coyote trapper will swear by a different brand or type.
pardon me for assuming, but you sound like a new comer to coyote trapping. The reason I say that, is you mentioned 6 double dirthole sets. while it is a good changeup type set, its not a set experienced trappers use much of at all, except in isolated sets.
Don't over think coyotes as far as THE SET goes. you will never quit learning to understand them, but the sets and concepts are simple.
make your sets natural- forget the double dirtholes- make a simple dirthole under a natural backing such as a weed clump, a yucca, sage- whatever is in your area. make the hole end back under the backing, make a slightly depressed pattern and put that trap out in front 8-10 inches.
poor visuals are te cause of more cooyte refusals than anything else in my book- I'm thnking oyur sets look unnatural- and they just want nothing to do with tme up close-
a good lure can get them closer- but unnatural, staged sets still spook yotes....trappnman
