If you have air maybe try to pickup a body saw at harbor freight or such only around $60-$80. I tried my cut off saw with a 1/16" wheel and found that unless you have an unbelievably steady hand the short cuts with a wheel result in a gap wider than the 1/16". I used an old cutoff saw blade ahead of my cut to hold the gap apart while I tack welded. The repop panels are a little lighter steel than the originals and I found some burn through (on the repop side) with a bigger gap. You can turn you heat down on the mig to bridge a wider gap but I found that more heat and a narrower gap leaves less overall distortion around in the joint and leaves a better penetration with less grinding afterward.
Just my experience using a Lincoln mig on gas (75/25 Argon/CO2) with 0.023 wire (tried a flux core setup before and had poor results)
