[12 piece bucket]

What causes the club to go to the left after impact? In other words, when I swing down and out, the forward takes care of the forward because it has no where else to go. But, what happens when the club goes too far out ? For someone underplane and too inside out, how do we get the club to move forward and around after passing the left shoulder? or do we want that at all?

You don't if you are using the 10-5-E plane line . . . but if you are using the Geometric Plane Line and you are too far out you are OFF PLANE. The solution is Tracing and look look look until you can see what On-Plane look like. Then translate that into a feel.