I just took another welding class at the college. On the wire feed simulator you weld constant with little side to side for a preferable weld. I was taught in high school to weld zig-zag for better results, Welding technology has came a long way in 20 years. It all depends on what type of weld, fillet, butt, lap or what ever you are doing. Vertical, horizontal and overhead are another story. I try and weld what I was taught, straight and smooth welds that penetrate.