Currently, once they are created, they generate individual Generic Splines. There is no option to edit the definition of the Face Curves as a group, especially when used in Features that accept a full Sketch as the Input.
Please vote on SPR 911732: Face Curves should be editable.
Ideally, the Face Curves command should generate a pattern of curves with all the nice options available in the Feature Patterns:
- Pitch and number of curves
- Up to Reference and Pitch
- Up to Reference and number of curves with equal spacing and offset
- Ability to Vary Instance