Hi Peter,
There’s 3 different scenario’s here, the way I understand it:
You having a WP account on my blog: meaning I need to approve and maintain your account in my WP install. Would work for separate posts and separate feeds.
You requesting access with IndieAuth: meaning you manually need to login each session using your own site’s credentials, and no account maintenance on my end. Would work for separate posts and feeds, and potentially for the same posts and feed on the same url as the public stuff.
You requesting access with AutoAuth: meaning your machine can do the logging in and then fetch content and feed at the same url as public stuff, no manual approval needed, and no maintenance on my end. (it’s indieauth without human intervention)