Just curious, what state requires the 80gr or less? I hadn't heard that rule.
My 25-06 I've only shot 4 coyotes with, usually use the littler guns. I used to own one that I shot 90gr Winchester PEP loads from, great at killing but terrible on hides. This one I shot 100gr TTSX Barnes through first and now have went to 100gr Sirocco II bullets. So far both have done far less damage than the varmint bullets to hides. They will exit, but the exit is the size of the tip of my pinky, not a big hole. I'm not sure if the lighter varmint bullets will stay in a coyote unless you load them down on velocity. You might look at a 80gr TTSX or something that will zip through without over-expanding. From a 243 or 6mm 75gr bullets will wreck a bobcat and get messy on a coyote not hit solidly in an area with plenty of yote to absorb the shrapnel.