Actually, most guys using MIG use clamps that hold the two parts in alignment and these clamps hold the gap .040" apart. Then they tack weld the parts together, remove the clamps and finish welding. Yes, skip around running beads about 1 to 2 inches in length.
You might try "pulling" your bead... ie. starting the bead and then pulling the welder away from the bead so you can better see the bead forming rather than pushing the welder over the bead.
Practice before you go to the finish job.
