7018 AC is made to work with AC welders - different then plain 7018. 6011 works as indicated. A slight whipping into and out of the weld pool. A slight Circle motion can work, but whipping is really the way most trade schools teach. But what ever technique works to get a good weld. I could go vertical up easier with 6013 then 6011. After burning enough 6011 on practice, I know can do both with "pretty" good results.

Oh, AC is ok, but the sooner you can get a DC welder, the easier your out of posistion welds will come . . . .