In our experience, the cup sizes are very accurate. While the back sizes are also very good, please note that its mostly made of satin, compared to 99% of bras which have lycra bands. Therefore, people often find they need to go up a back size.
Everyone has their own way of putting on their bra. However, we find that the only way for a bullet bra to sit correctly, is for you to bend over, so you're back is horizontal, and shuffle into your bra. (we call it 'the gravity shuffle!) It helps you to fit into the shape of it.
Matching knickers and deep suspender belt available.