Zane,
I really think the best solutions are going to be either an inert gas
method or the small bottle method (I guess you could do both). You
mentioned the small neck of a 187. One thing to try might be to fill
all the way to the top (since they are screwcap) so thee is no neck
air. If you could minimize agitation (pour slowly and smoothly through
a funnel) and pour immediately after opening the "master bottle" it
might help. And then refrigerate.

I'm not sure anything will give you a method that is indistinguishable
from a freshly opened bottle for 2 weeks. I find it helps a lot to have
a wife who likes wine (and friends who do). And I still produce a lot
of red wine vinegar in my crock!

Another option of course is to buy 375s. That way you'd only need to do
one 187 per bottle if you were drinking 6 oz or so a night.