Maybe this will clarify things? A very relevant article appeared in the December 2013 issue of
Rag & Tube, the magazine of the Antique Aeroplane Association of Australia. It was written by Mark Miller, Chief Engineer of de Havilland Support Ltd in the UK - from personal experience he's a good guy, friendly and very helpful. I would also argue that he knows about as much as there is to know about de Havilland designs. He's also very "hands on", having restored a truly immaculate DH.84 dragon.
The main thrust of the article is DHSL's concern about the amount of erroneous information floating around about dH designs, and that people may well take short cuts not being fully aware of the implications. In general the Tiger Moth features primarily here, although the Chipmunk gets a few mentions too...
It was written before the VH-TSG accident, and contains this gem:
"And the Tiger Moth, did you know, actually falls short of contemporary strength requirements for the Aerobatic Category! It was accepted at +5g/-3g (with 50% in hand before ultimate failure) only on the premise that there is limited scope to impose exceedances on such a high drag and low speed airframe."
There is also a discussion on biplane load paths:
