If you get the American champagne-style bottles, they'll take a "standard" North American crown. I just had issues with about a dozen crowns leaking under high pressure, and a few crowns flying off unexpectedly. They were carbed to between 5-5.3 volumes at that point, and at a warm room-temp. If you can keep them colder (60*s) or pressurize them lower (I dunno, <4.5 vol?) you probably won't have the same problem. I used a double-lever and a bench capper on those bottles, and I think the double-lever capper actually gave a better seal than my bench capper.