At an exact 1:4 scale, using a Scale Ruler. Surprisingly, it fits my mannequin. So I dressed him, in a Chinese way. Ｉ ｓｈｏｕｌｄ ｍａｋｅ ａｎ Ｏｂｉ ｓｏｍｅｔｉｍｅ！
One thing that I am not sure about is ... the dangling part of the kimono sleeves, as well as the underarms, were unclosed (according to my understanding of the Japanese instruction book).
Although it's a scaled version. I did followed the instructions maticuliously (given that I didn't understand Japanese, I spent quite a long time to figure out the illustartions). If you go to Wikipedia and search Kimono, you would see that my scaled kimono has everything except the over-collar, which was too thick for me to sew over the narrow inner-collar. http://en.wikipedia.org/wiki/Kimono
This is the book I used. I got it from a store called Little Kyoto (or Little Tokyo) from Kensington Market two years ago.