This is now in 14-point size. This is a point size of 20. And this is a really small point size of six. The default point size is 10. If you use the .ps command without a value, groff reverts to the previous value.
Line spacing is the vertical spacing between lines.
Vertical spacing is not tied to point size, so it should be adjusted manually. As a general rule, use a vertical spacing about 20 percent larger than the point size. The default vertical spacing is 11. This is in 12-point with 14 vertical spacing. If you use the .vs command without a value, groff reverts to the previous value.