I use decoy dogs as well and also use Mtn. curs. I have one yellow and one brindle. I have a half catahola and half Mtn. Cur in training. I use mine on the trapline as well and they get pretty rough on those trapped coyotes. I skin my coyotes and believe me they can punch holes in them and really make ribs pop when they get a hold of one. It is amazing how strong and rough the cur breed can be. I have luck using them in the breeding season (feb&mar) as well, usually the big male coyotes come to them, I have had some big time stand offs, but never a full blown fight while decoying. I have had 4 coyotes on one dog and it was getting pretty hairy until two of the coyotes took a dirt nap.
I think the trapped coyote is a great way to get a pup to know what your after and also gives them a chance to get ahold of one, but be able to get away from it if needed. I have never had one back-up much, usually the first time in the are a little leery, from then on its all in. Which is pretty standard for Mtn. Curs, not much backup in them.