I'd like to have three levels of stacks, and then tag from there.
I've followed the suggestion I've seen many places to create three notebooks or stacks of notebooks--00 INBOX, 01 PERSONAL, 02 WORK.
Within 01 PERSONAL I'd like substacks for things like HOUSE, HOBBIES and PLACES.
I tore my hair out until I realized Evernote will only stack notebooks once (no stacks of stacks).
In addition Evernote has changed so much so quickly that most of the things I see no longer work as seen/described--not even on official Evernote videos..