You say metal plane how thick is the metal going to be if 16th thick going to be awfully tough to do if thicker there is not a ton of difference in Flux Core welders mostly the duration of the weld before letting the welder cool down. Argon shielded welders give a much cleaner weld ( less spatter and clean up ) and easier to use unless out in the wind. The one I purchased has the option to add the argon if I so desired.
When I was younger was building a boat trailer from galvanized pipe arc welding in the winter time in a closed garage woke up the next morning thought I was going to die could hardly breath. Back then never heard of galvanized poisoning but I learned the hard way of what it was.