A torch will cut ar 400 just fine, I think 11018 runs just like 7018 but if you have alot of vertical welding i would get some coreshield 8 (fcaw) or take the blade off and lay
it down so you can burn some bigger rods and actually get it done.
At my last employer we would always take them off, lay it down and most all the welding was done with 3/32" NS3M (fcaw) wire, you have to have about a 500 amp machine to run that stuff though. we were usually changing the liner as our d10s were always pushing 631 scrapers.
I would seriously get some coreshield8, it a low hydrogen weld, it will weld circles around smaw, and its awsome for out of position welding.