What is best practice for working with my current billing solution outside of Karbon

If you are an Admin, you can export work and/or time, and manipulate the data in a way to help you invoice through your app of choice. In Karbon, you will see various download and export buttons to get to that data if you are an Admin.

There is also a more comprehensive export that a Karbon CSM can provide. Just ask them at support@karbonhq.com or read this help article: https://help.karbonhq.com/en/articles/5433219-how-to-use-time-budgets-to-complete-billing.