shoot whatever you'd like, my friend! One gun or twenty, you are on the right side in the us vs them gun discussions.
Your .243 and your 7-08 with even light-for-calibre bullets will almost certainly leave a sizeable exit hole on a coyote regardless of range. If you want to sell the fur, that is a disadvantage.
I myself agree completely with you that the only good coyote is a dead one, and I do not wish to salvage the hides, so if I blow them up, that is a GOOD thing. If I send Wile E to his maker with a gaping entrance hole and a fist-sized exit, he is not going to be eating any more fawns.
I would not use a .325 WSM on deer, but if a man can only afford one gun, and that is his choice, I respect that. He will almost surely be unhappy with damaged/blood-shot meat, but in the end it is HIS meat he is wasting. Your choice of .300 Win Mag for moose was a sound choice, and the fact of lost meat could be due to a hundred variables (notably bullet choice, bullet placement, bullet deflection (ie hit a tree before it hit the moose), etc etc etc. You could just as easily have been presented with a 300 yard shot, for which the .300 WM is well suited, and got a perfect broadside shot and hit no ribs going through, with virtually no lost meat. EVERY shot on game is a crap shoot.
Doug