This article is generally good, but a better model has come out of I need to pull and merge from what was learned in the WordPress instructions currently being finalized. Once this is done, will extract the ACLs from there and merge here for a final article..
Basically I have given up on ACLs as they do not behave the way I would like and the creators think that is ok. Instead, I am looking at application level virtualization to define control.
What are ACLs?
Advanced permissions beyond the traditional Unix permissions. It has powerful features such as being able to give permissions to more than one user and more than one group.