Not to be contrary and please continue your research and post as there can be clues missed, but I believe the one and only time that Q has ever shown us a watch depicts a 12 hour watch and that is what they are using to talk to us right now. If they start talking in military tine and Zulu in the future, we'll follow.
When Q says wind the clock do you think, by Q's language, we might be given that imagiery of an old-fashioned wind-up 12-hr alarm clock by intent?