Add a feature to project a transparent cone from a targeted docking port that visualizes the volume that the player's craft's center of mass must be within in order to dock successfully.
The visualization could look similar to the this depiction of the ILS system airplanes use:
https://www.aopa.org/-/media/images/legacy/aopa/pilot/1504p/1504ppeils.jpg
The length of the cone could be a fixed number of meters, or it could extend to the range of the player's craft to the docking port.
Interesting, though the Navball/sphere works!