How to replace *_args in custom executor with single command line?

I’m in the process of creating a custom gitlab runner executor. Currently the runners.custom section looks very repetitive:

      config_exec = "nomad-gitlab-runner"
      config_args = ["config"]
      prepare_exec = "nomad-gitlab-runner"
      prepare_args = ["prepare"]
      run_exec = "nomad-gitlab-runner"
      run_args = ["run"]
      cleanup_exec = "nomad-gitlab-runner"
      cleanup_args = ["cleanup"]

Is it possible to get the “args” stage part from an environment variable? To get that, if it is missing, should I post a feature request to Issues · / gitlab-runner · GitLab ?