If measured well,it can fit well,at least for chastity belts;even if I know some people needed some bending.I dont't notice it in my case,but not totally sure,my parents kept the chastity belt when I was not wearing it,during my training.
Drilled holes in the bra is a good idea,if my parents want me to wear one in Summer,I'll ask for it.I guess it is done while preventing to give access to the most sentitive part?