The next step from this is the django-configurations package. While it's not perfect, it does help when settings get very complex.

We've got a Django site that we run in production for different partners. We've got 560 settings, and then dev/test/prod configs for each partner, plus we vary the list of INSTALLED_APPS per partner. django-configurations is pretty nice for making this all manageable, and mypy helps to make sure everything is consistent.