Re: custom ocio creation for nuke
Typically OCIO configs are created using the OCIO Python API. The make.py file you referred to is one such script, which you could modify as needed and run with Python to create a new config. Here's another fairly simple example of a config authoring script for your reference:
These scripts construct a Config object (with all your added ColorSpaces, Looks, and their Transforms), which can then be serialized to YAML text data and written to a file, typically named "config.ocio".
One you have a new config created, set the "OCIO" environment variable on your system to point to the created "config.ocio" file on disk and Nuke will then use your config automatically. Alternatively, you can point Nuke's root "custom OCIO config" knob to your config file for the same result.
Please refer to the "Config syntax" section of the user guide for an explanation of the resulting config file syntax and key concepts you should understand when authoring a config:
And reference the "Python API documentation" in the dev guide for a better understanding of the Python interface used by the above mentioned scripts:
I hope that helps,