Most of my sets run about 15 minutes and 20 on the outside. Staying still is one key I've found to consistency. Got a friend whom I've always thought was a good caller and he tried the misting thing for a couple of years. His percentages were not any better than mine. I really didn't see any advantage and him and I both came home stinking.
I've hunted with him a few times and the wife wouldn't let me in the door til I threw my clothes in the washer and took a shower. If it makes you feel good go ahead, but my limited experience seems to say it doesn't make a darn bit of difference.
Of course I also rate it right up there with wearing a Ghilli suit. I do wear some camo, but have shot hundreds of coyotes with nothing more than a brown shirt and blue jeans. I'll try dragging a Ghilli suit through the brush when the coyotes start shooting back.
Make your calling simple, call short periods and do a bunch of sets a day. I like calling edges, draw and canyon edges, field edges, woods edges. Pick places where your not backlighted and can see a good area with the wind to one side or in your face. If your calling more than 20 minutes there's a good chance that 1. there are no coyotes within hearing range or 2 they've been educated and won't come to a call.
If your dragging so much stuff around that it takes 10 minutes to set up your bringing to much stuff. This is where the KISS principle does seem to pay off.
Mist if you want, wear Ghilli suits if you want, crawl half a mile into a set if you want, but dollar to a donut I'll be killing coyotes while your doing all that stuff. I've never seen a confused coyote, just hungry ones.