Another Azure AD app question - Debugging

What exactly is the suggested development workflow for debugging Azure AD apps?

Our scenario is:-

1. App created as a .net (MVC) site with work or school account authentication

2. App run and debugged on local visual studio server, automatically creating the Azure AD object with a localhost reply URL

3. App published to server and reply url changed to make it live.

4. I want to be able to make changes to the local copy and debug it and then publish the changes

I cannot seem to do this without manually changing the Azure AD object reply url, which would down the live site. I can see it's possible to have multiple reply URL's, suggesting it's possible to do both but I've had little success in finding a way of doing it that actually works.

This seems harder than it should be so I suspect I'm doing something daft.