Never shot coyotes with a 17hmr but from what I have read around here, stick with the .22 Mag. I have killed several with the .22 mag and so far haven't lost one. Shot placement is the key when hunting with a rimfire.
It's like SC don't want people to hunt at night. They want to make it look like they do but they impose so many restrictions, it keep the hunter handcuffed. I won't call at night because your not allowed to use a scoped weapon. What better way to identify your target than with a scope.
What part of SC you in?