To heckle, the artist had a vary opinion of how big the bust-size of the Shiratsuyu-class. Still I do more see Yuudachi, Murasame and Umikaze having a well endowed breasts. Shigure having a modest one, and same deal with Harusame and Yamakaze (depends on artist if it's bigger or yeah)
For Kawakaze, I'm sure she isn't literally flat though-