I would set your MIG on one of the higher settings, for anything in the 1/4" to 3/8" range. Just be sure and have plenty of heat. Turn your shielding gas up a little more than normal too, to help avoid too much spatter. I usually stuff a damp red rag or shop towel in the axle inputs, just to avoid spatter getting in the splines. I wouldn't recommend using any kind of stick/arc rod. 7018 3/32 is going to leave a lot of slag that is going to be hard to chip out.
