How do we add a custom/self compiled authlib-injector agent to a PollyMC instance?

[oneechanhax]

I have a self-compiled authlib injector that I got simply from downloading the code on github and running gradle on it.
https://github.com/yushijinhun/authlib-injector/tree/master

Just for my own curiosity, how do we add this custom authlib jar and get it working under pollymc?

So far checked:
The authlib injector wants some sort of input after the javaagent argument, looking at the "Install Agent" it looks like it would work, but it fails to launch suggesting it wants a Authentication server to use.
Checking the pollymc metadata json file for the library, it doesn't have a easy way to do any changes to the usage of the command.

I seem to be at a loss for adding a custom injector, trying to replace the installed one with a custom one gets reverted due to the metadata that gets downloaded for the list of library files.
Is there an easy way to do this that I have missed? (I'm using Drasl on a private server on 1.7.10) https://drasl.unmojang.org/

https://github.com/HMCL-dev/HMCL they have the following option to achieve the effect I am looking for:

-Dhmcl.authlibinjector.location=<path>

[oneechanhax]

I appear to have gotten it to work with this:

-javaagent:{/path/to/authlib-injector.jar}={Authentication Server URL}

into the custom java args.

The only issue I have with this is that it isnt tracked by the instance, and it links to just a random file i have to keep around.

Maybe this needs a feature to add a auth-injector jar for global and instance specific use that can get tracked by the instance and cataloged alongside the forge libraries.
Im unsure how that would work