I wrote this post in another thread a couple of days ago, but it is relevant here and worth a reprint . . .
In a Rhythmic, On Plane Golf Stroke, the orbiting Clubhead moves outward -- to the right and towardsthe Plane Line -- until it reaches its Low Point. Then, and only then, does it begin its journey inward -- to the left and away from the Plane Line.
The Flatter the 'exit' Plane Angle (after Impact), the more 'left' the Stroke will appear. But, this is a matter of Plane Angle, not Plane Line. The liberating truth is . . .
In a geometrically-correct Golf Stroke, the Clubhead never moves away from the Plane Line before Low Point, and it never moves toward the Plane Line after Low Point. So, it's Swing right, and then, Swing left.
As a simplified alternative . . .
Trace the Straight Line Baseline of YOUR Inclined Plane!