A lot of chassis builders run their machines as 'strike-arc' and don't use any "throttle". Not so sure about off-road chassis guys, my understanding is that this is most common with drag race guys. The difference mostly being that drag race chassis are single pass welds while off-road have a root bead and then a 'wash weld'.
I tried this just to see if I could do it and it clearly takes a lot of practice to be able to instinctively set the machine correctly.
