Thanks for the quick response.
I have given some thought to other options than search. Most of the problems come from a document not belonging 'cleanly' to a given area in the current folder structure (which was admittedly put together poorly), or else needing to be in multiple areas. Multi-filing might work, but I like the idea of tags more. I suppose I'm influenced by google mail where I find things by either searching or looking through specific tags or combinations thereof - hierarchy location unknown and to me irrelevant. Security as tags change is a question I asked earlier and I'm satisfied I can trigger the correct application of ACLs. Whether it's a good idea to do so, I've not convinced myself yet.
I'm leaning towards a structure where new documents get autofiled in some random folder (perhaps based on the hash as I saw somewhere else on these forums) where the folder permissions are wide-open but the document permissions are locked down per user desires. Users that can see the document can then apply further tags to it, some of which may open that document's permissions to some extent. Groups would do the same thing and be simpler, but I want the group list to be static and admin-controlled whereas the tags to be dynamic, user-controlled and useable in filters/searches.
Still new to this and trying to break out of my old DM mindset, and I appreciate the advice.
Chuck