Well played Keith, although I usually find the open bottle on counter in morning while trying to fumble a nespresso pod into the machine.
On a serious note, I don’t find much difference between a stopper overnight in fridge and an open bottle in fridge overnight if drank the next evening unless it’s something really aged.
My favorite is the one I find first rummaging through the basket of wine accessories. Honestly, I can’t say I’ve ever noticed much difference among the 5-6 we have, which range in price from free at trade events, to very cheap purchases, to one that was a gift and almost certainly cost way too much.
I just re-cork it with whatever traditional wine cork I have laying around. Using this method I’ve always had bottles last up to two nights. I.e. open on Friday bottle is still sound on a Sunday. Never tried stretching it longer than that.
We have not found a need for a specialized champagne stopper. Here’s what we use for everything (and it may work even better with a champagne bottle because of the narrower opening).
I have a few different stoppers, a couple like the one Neal posted and another (Rabbit) that you twist the top to expand the part that inserts into the bottle. Like Sarah, I find they all work roughly the same although I prefer the former clamp type.
At home, I get four glasses out of a 750ml of Champagne and the stoppers work well for my tastes. As far as bubbles, the effectiveness on the last day is more about the much larger volume of air than the extra day.
I have an acquaintance who loves Champagne, but the intensity of the bubbles is one of the most important aspects for her. So, she doesn’t think the stoppers work well, at all, even if only a single glass was poured the previous day.