A lot of the girls look pretty nice with a more mature look!
Here's another example of an adult look for Ayumi from one of her "Great Tankery Operation" character cards:
https://static.wikia.nocookie.net/gup/images/b/b1/AyumiStewardess.jpg/revision/latest?cb=20180603192118

I guess those breastplates are not standard issue?

Clothing makes the ladies...except if they're wearing...fake breasts.

XD