Clarification on oauth config for production vs development

[GNRSN]

Hi, I'm just curious if I've understood this correctly.

I'm using github for authentication; from the image in the auth-proxy readme I inferred that I should have two ouath "apps", one for the production deployment of next and one for the auth proxy?

For the expo app, in getBaseUrl, I should then return my production url when not in local-dev, and replace the http://{localhost}:3000 return in local dev with my auth-proxy url?

Did I get this right?

Also, out of curiosity, why not use the auth-proxy for production as well and have a single oauth "app" per identity provider? Does this have any security implications?