Using the Width tool, how could you make the stroke on the top path match the bottom one?
Drag the selected width point left until it snaps to the same position as the adjacent width point.
Delete the selected width point.
Double-click the selected width point and set the Total Width value to 0. Using the Width Tool in Illustrator
Press and hold the Option (Mac) or Alt (Windows) key, and drag the selected width point to the left.