It works fine, but two new "problems" arise to which I have no answer:
1) if you intend to close the file (using File>Save As of the "X" icon at the top) and then decide to not close (cancel) the AutoClose routine has already worked and set the template to nothing (""). This should not happen, but I see no way to trap the cancel choice and act by either not removing the template attachment or by re-instating it
2) If the template has QAT buttons, once a document based on it is re-opened all QAT buttons appear twice (I guess this applies to template made ribbons too). That also should not happen but no idea how to prevent it.

If someone has a suggestion, I'm all ears!