Right. That makes a whole bunch of sense, and it's what I was thinking I should be heading towards. Let me see if I have this right: to
hide/restrict a resource/element from one user group requires an equal and opposite
enabling for another user group of a higher authority level. Is that a correct statement?
Maybe I should have outlined this at the beginning. The plan I have to follow is to divide the resources into particular areas along the 2nd lvl resources. For each area there will be 2 types of users (roles): Editors who create/edit/save/move resources, but don't (un)publish or (un)delete; Area Managers, who create/edit/save/move/delete, but not (un)publish; lastly, Publishers will have all of those permissions including publish, but they aren't restricted by area, and can move resources between areas.
Then above the Publishers is the SysAdmin (totally different access permissions), then the Site Owner (inherits all other access plus some, but still not full), then me as Site Admin. On top of this, I'm using multiple contexts. Because it wasn't complex enough already

! But I can see how your explanation just now will work for that, so I'll give it a shot and see if I can get my head around it.
One question I still have tho; how do the access permissions for particular contexts work with all of this? It would be great to minimise the visibility of some of my contexts, both in the front end and in the manager.
Lastly, there's no specific documentation on the actions listed in the default policies and policy templates. So for instance, the Load, List and View policy is obviously the policy needed to only allow viewing of a resource, but there's no comments or online documentation to denote this. Can that documentation be added to Dashboard?