To put it in perspective regarding slim women convinced they're a 34 or 36 back, I'm a seriously dumpy size 14 and wear a 34 back - could wear a 32 in some styles.
Anyhow, I often have serious problems with heat rashes in the summer, so I've been looking for an armoury of cotton bras, since I currently have none. My most usual size is a 34F and I have the dreaded spaniel ears, which doesn't help matters at all.
A lot of the cotton styles stop at DD cup, which is understandable but annoying.
I've tried this one, which is supportive, well structured and such a lovely shape, and sits beautifully on my back - no blubber at all. The cups on the 34F were massive and the 34E was just all wrong, though - I had the pooling in the bottom problem and no amount of scooping would make my boobs sit in the right place and stay there.
I've settled for some of these which actually fit quite nicely, apart from having a minimising shape which I'm not entirely fond of. With 20% off they were a bargain at £17.60, so I've kept them. I'm not convinced they'll last me long, though.
So bra gurus, any suggestions of what else to look for would be gratefully welcomed.