Same size. I've used the Fender silver ones from Guitar Center. The iluak ones are a little pricey but add a touch of class
http://iluak.com/index.php?route=common/home
This guy does some classic looking buttons in both bone and fossilized mammoth ivory. He also offers bridge pins (Kanile'a BTW, are size 2C), saddles and nuts.
http://guitarpartsandmore.com/
They look great Kypfer. Are they made of metal?
thanks for mentioning the Kanile'a bridge pin size. A few days ago one of mine came flying out like a rocket as C string was at full tension. I still have not found it I am using a guitar bridge pin as a short term fix, but it obviously is a bigger size as it only goes about 3/4 ways in.