Yep mig would be easier, tank made out of thin metal, and yes blow a couple of holes. But learnt my self to bridge holes and grind smooth, as if wasn’t there .
That's a good skill to learn but hard work.
I'm lucky and have mig, tig and arc and when I get beat trying to fill gaps with arc I fire up the mig.
Are you thinking of changing to a tear drop tank?
You could shape a tank from a solid piece of steel, or made it out of much heavier plate welded with the arc, and grind to the shape you want with a 4" grinder and a flap disc.
Just a thought.