Please try an early release of gridtools and try to utilize this example for converting your ROMS grid to MOM6. We ported the original code in Kate's repo to gridtools. I have been working on testing it before formally releasing it.
A collection of grid generation tools. Contribute to ESMG/gridtools development by creating an account on GitHub.
github.com
You will need to clone the gridtools repository from github and use the "rel033" branch to use the updated code and example script.
$ git clone
GitHub - ESMG/gridtools: A collection of grid generation tools.
$ cd gridtools
$ git checkout rel033
At this point, you should see mkGridsExample13.py in the examples folder.