Good input. The layer idea came to me as I was typing at beer:thirty on Friday afternoon as a means to provoke dialogue on various way sto set-up drawings. I've been thru similar exercises on the right way to set-up part numbers (non-significant seems to be the key) and wanted to take that thru the entire engineering process. We have moved from a significant part numbering system to non-significant (no, I didn't say insignificant

system using 6 digits with 2 check digits (8 total).
I just ordered "Engineering Documentation Control Handbook", which is decent. It discusses the various "documents" that may be used in a business.
(1)Design documents (product specs, part drawing, schematic, etc)
(2)Manufacturing docs (process sheets, fixture drawings, QA inspection drawings, etc)
(3)Support Docs (manuals, spare parts, etc).
It sems to be a sizeable task to make standard templates for each, but I'd like to get most of it taken care of. Also, the disadvantages of significant codes apply to drawings as well, but we use the same drawing for producing parts of differing materials. Therefore drawing numbers need to be common to the PART DESIGN.
See, you guys in big companies don't have all the headaches....