For the use you are describing I'd go with a 220V machine in the 175-180 range. As long as you buy a decent brand (Hobart, Miller, Lincoln) any of them should do the job.

About the only job that I've done that required a bigger welder was narrowing a D60 axle, the 175-180 class machines arn't up to 1/2".

Chuck P
www.oldjeep.com