As requested, here are some variations on opacity of stitches, for comparison. Also I threw in a few gradients just for fun. My goal is to make pretty, readable charts :)
Swatch with 50% opacity:

Swatch with 60% opacity:

Swatch with70% opacity:

Swatch with 80% opacity:

Swatch with 90% opacity:

Swatch with side gradient at 90% opacity:

Swatch with radial gradient at 80% opacity:

Swatch with radial gradient at 90% opacity