Yeah, they need to prepare a stylist or ask Mama Hanyu at every comp! And I'm sure he'll run away from being bothered. You will see why if you have a look on some of the photos here.
How to wear kimono (men) --preparation
Btw I think most of the young people nowadays need fillings anyways when they wear traditional Kimono, bc kimono best fits the body like... a drum since kimono is characterized by straight-line cutting.
In case of yukata, you may not need fillings, since yukata was originally a casual wear to put on during/ after bath. It was originally something like a pajama or bathrobe. Later people came to wear it when they go out for casual occasions such as summer festivals but as such it is considered to be a very casual wear. But as somebody said, Yuzu's attire is very formal, and actually this black Hatori / Hakama with family crest can be worn by a bridegroom at the wedding.
Edit: That's why wedding-related words came out in my TL