I've always used the standard size, and have never had a problem with them fitting into a wine bottle. I haven't tested them in any other kind of bottle.
I agree that Ruth's stainless steel stoppers are the best; I have a few of them in my shop that I reserve for special occasions. And I met her at Totally Turning a few years ago, and found that chatting with her was a really pleasant experience. If I were making stoppers to sell, that's probably what I would use. But I don't sell stuff; instead, I give them away and don't want to spend that much on materials. When we went to the neighborhood Christmas party on Saturday, I took the hosts a bottle of wine with a stopper tied to the neck.
When I first got into turning, I used some of the plated stoppers sold by PSI - they were terrible. The plating corroded and eventually flaked off. Later, I switched to the PSI silicone and dowel design which I used for quite a few years. More recently, however, I bought simple silicon sleeves alone because I don't need a dowel - instead, I turn a long tenon on the bottom of the stopper that the sleeve slips over.
nilesbottlestoppers.com
