Never used it for open bottles, but have used inert gas to fill
headspace on carboys. One of those cans (about quart size) last me at
least 3 years of winemaking.

FWIW, Cook's Illustrated magazine just did a comaprison of various
products to preserve half-used wine bottles. They concluded that none
are as good as one would want, but they recommended vac-u-vins as the
most successful at minimizing aging of open bottles. Never used one
myself, so I can't personally recommend it, but there you go.

I like the 375 bottle and T-cork idea. May have to consider that
myself.

Rob