I’m a strong advocate of keeping the scope on the lowest power possible, and agree with the poster who said that you almost always have time to dial it up if the dog is out there a ways, but almost never have time to do much but shoot if he is close.
I am pretty good at predicting what direction I will shoot the coyote but not so good at predicting distance. I have laid the rifle on a rest, pointed where I expected the coyote, and had the dog in the scope when I leaned forward to grip the rifle, without any movement. That extra large prime coyote was 35 feet away. I’ve had called coyotes within touching distance, and a good number that came in so close that I couldn’t focus on them with 2 power, when calling wide open spaces. On a grassy prairie one belly crawled up to me and then pounced. Scared the daylights out of me. I'll never foget the shock on that coyote's face as it slipped down trying to reverse and slid toward me with its feet churning for traction on the slick matted grass right in front of me. I'd predicted a long shot on the open grass. I missed.
Most of mine have fallen to a 2-7 Redfield, then a Simmons 3x9 and now Leupold 3x9. I keep a scope set on the lowest power, always, till I start to mount the rifle to cheek. The best coyote shooter I’ve ever known used a fixed 4 power on a heavy barreled .243. He shot five out of a pack of five while standing in place one morning, then picked up two more a few minutes later the next valley over.
Calling style and set up has as lot to do with how close you draw in called critters. I started calling as a bow hunter so I know my set-ups are often conciously designed to be close when the action starts, even with a rifle. If you call from a Texas tower, they won't as likely be in your lap. Come to think of it, it's a hunting style across the board: Moose, too close to focus with 2 power; bear, too close to focus with 2 power; elk, powder burned (4-6 inches?); deer, 8 feet, and a 176 scoring muley at 35 feet. I didn't shoot it but my partner shot a very nice Stone ram at about 8 feet range, with a .338. Be ready for the surprize close up shots, and you'll have time to dial up for the long ones.