6010 and 6011 have worked for me.I have had less success with 70XX rod.Clean metal is important and post weld,work the metal hot,near forge welding temp.The last part is important,as I found out.I was told that by both Bill Epps and Jock Dempsey.Hey why would I listen to those 2 guys?.Turns out it cracks and even breaks if ya work it too cold.
As for the "tradition".I have noticed that blacksmiths tend to be forward thinking people,problem solvers.My guess is if the smiths of old could have replaced a mule powered board drop for an electric driven one,they would have.If they had access to propane they would have used it.An arc welder is just another tool [mmm tools,I love tools].Whatever it takes to get the job done.