Don't go slimmer; that looks like a good fit. There is no 17 cm cut. Sometimes the cuts run smaller than usual, so 21 cm cut measures 19 cm and 19 cm cut measures 17 cm...or somewhere in between that. Strip destroyed jeans are even less than 17 cm when you get down to the smallest sizes.
Arturo, 5HH = F/W 05. Just remember # = year.
I've now had my first experience with petite sizing. Got a white hidden-button dress shirt with bee from VOTC in 36P, and it's TOO DAMN SMALL!!!!! I'm so disappointed. It's a really nice shirt, and it actually fits me perfectly everywhere except the chest. If I took a deep breath, I could pop a button off.

I guess I'll be sticking with 37's.
However, I'll probably be getting a size 42P shiny Strip notched-lapel blazer.
And I'm excited for my white three wolves sweatshirt to get here! Does anyone have one? Is it pretty nice or will I be disappointed?
Also got this stuff recently, for those of you who don't frequent the Secret Shopaholics thread. The polo was a major impulse buy on very little sleep just because it was my size.

I'll probably end up selling it. Click pictures to enlarge...