Make redirect url to satisfy multiple instances

That is an interesting challenge. Automating this might be hard to do within Simple OAuth. This patch appears to change the redirect_uri for all consumers, but I don't think that is a solution. In my experience the redirect URI is often a URL external to the Drupal host (for integrations with other services) so you would never want to change this value even in non-prod environments. Maybe you are using this for a headless app on the same domain?

Maybe there could be a boolean on the consumer to indicate that the redirect URI is the Drupal host, in which case you could conditionally use the logic in this patch.