Using a usuba for tournes and recommendations for usuba length

I've read on this forum about Japanese chefs who do a six sided cut on their vegetables using a usuba that looks very similar to the classic French tourne. However, I can't seem to find any examples or explanations of this through Google, and I was wondering if anyone could provide either for me.

Also, I'm planning on getting a usuba soon because I've wanted to do katsuramuki ever since I saw it, and I've settled on getting a Gesshin Uraku. I'm leaning towards getting the 210 mm because I don't see why the shorter 180 would be more useful. However, I'd like to use the knife for tournes (or whatever the Japanese equivalent is) too if possible, and I feel like there's a chance that the shorter length can be more useful in this case. I know this type of stuff varies based on personal preference, but can anyone describe some personal experience with using different lengths of usuba?

Most cuts with a usuba are push forward type. The six cuts your talking about would probably be cutting a hexagram, and then doing something reminiscent of a katsuramuki cut, to form a flower. I suggest you purchase a mukimono book if you really want to get into the usuba.

Do you know of any good mukimono books in English (or French)? I have "Japanese Kitchen Knives: Essential Techniques and Recipes" which is very good, but doesn't cover too many of the decorative cutting techniques.

The Decorative Art Of Japanese Food Carving. I also wouldn't bother trying to tourne with an usuba. Seems a little difficult to me. Typical length for an usuba is 180mm or 210mm. 210mm is definitely better/easier. more blade makes it easier to slide the knife during the action for katsuramuki