Just a passing thought, rather than having multiple arc/return leads etc lying around is it feasable to just make up a couple of extension leads using dinse plugs/sockets or is this a no no?
The genny welder i have is a 240amp and it has 10m leads but because of the size and weight of it, sometimes its easier to leave it in the van or on the ground and run leads to the welding site so the longest extension leads I would need would be in or around 40m giving a total length of 50 meters.