Just out of curiosity what model welder? Lincoln has some confusing ratings on some of their smaller ones but I am guessing a 175 class wire feeder. I like 10/30 on these as well as a 10/30 for the air comp. The comp would fly with a 12/30 circuit but likely the run is short and the 10 wire doesnt hurt anthing, good for motor starts. You are right about the availability of dryer cords, especially 3 wire, but they are not grounding type recepts. I would be tempted to leave some provisions for surface wireing in a working shop, makes it so easy to add as needed exactly where and when needed. You can plan a lot but I fid that machine locations dont always work out according to plans and when the wiring system is flexable there is a lot less temptation to leave things "as is" and just put up with it. Remember, God didnt set the machine in the first place you put it, it can be moved if its more convenient.
