Without a doubt, 58 gr. V-Max. Nosler 55's are too hard and rip 'em up pretty good, Speer TNT's are ok but I believe only go as light as 70 gr and in my experience were too unpredictable when it came to pelt preservation, Sierra 60 HP's shot well but not as well as the V-Maxes (haven't tried the 55 Blitz), and Barnes 58's didn't shoot worth a s**t.
I call coyotes and the action is usually pretty hot. I've hit 'em as close as 12 yards on the dead run straight at me, straight across me, running away from me in every imaginable direction, and sitting at 300 yards, yipping at me like a possessd ex-wife.... Man, I love shooting coyotes! Of the .204's, .223's, and 22-250's i've used, I'll take the .243 any day. Awesome 'coyote' power, great accuracy, and WAY more one-shot kills than any of the afforementioned.
I use light bullets for two reasons; speed (as you will find is useful when all the different scenarios unfold when calling coyotes) and bullet mass. My theory is that a lighter bullet sheds energy easier/earlier than a heavy one, helping to mitigate unacceptable damage.
When loading to max or near max, you have to watch how you hit them. Hit them lengthwise (either end works well

) and the V-Maxes won't exit even at velocities over 3800. Aim for the off-side shoulder when broadside and the bullet is usually stopped by the inside of that shoulder bone. Raking shots, however, are a different matter. If you can sneak one in behind the ribs on a coyote runing away from you at a steep angle, you'll likely be alright. Catch a near-side rib and you're sewing a throw rug into that sucker! I hate sewing.... These results are the same every time.
The load that ended my development is 41.2 grains of IMR 3031 in Winchester match prepped cases with CCI BR-2 primers installed. This shot (dare I say) a hair over 1/4" THAT DAY. Pretty hard to repeat but I can easily shoot inside 3/4" any day, all day with this at 100 yards.
I've often thought about trying Varget as well but never got around to it. I hope this helps and let us know how it turns out for you.
Rooster