How to enable non-admin user to modify ACLs to docs

[afaust]

Basically it is safe to assume that permission set at a lower level take precedence over a higher level, and more specific permissions take precedence over less specific ones. I.e. if user A has been DENIED Consumer permission but has been ALLOWED Read permission, that user will be able to read content items. If user has competing permissions set on the same level (directly or via membership in multiple groups), then the DENIED will take precedence, though the "more specific" rule still kicks in, i.e. a permission set to user specifically will have precedence over a permission set to the group.

It's all quite logical...