I did ask to be fitted in a lingerie store, but the kindly & understanding lady said they don't stock bras with more than 38" band size. I am a full 40", with a small cup but carrying a woman's nipples so I hate padded bras which push my nipples flat. So I have to buy from specialist online sites. For example, I can buy lovely sexy lace bras in my size with ample nipple room in the cups from "touchable.co.uk", but boy, are they expensive!
An intimite bra fitting from that lady would have been a heavenly experience, though!
But I digress. A really sissy friend had recommended me to try "Fashion Forms Strap Connections". This amounts to a third horizontal bra strap which pulls the shoulder straps gently together. It is less fierce than the "racer back " clasps and should hold my straps in the middle of my back, so I don't show from a dropped strap over the shoulder or an upriding strap at the nape of my neck.
The disadvantages, apparatly, are that it is difficult to put on without help and it adds to the bra strap "lump" problem under a tight top. If you are under-dressing there is now the back band & fastener, two normal straps with their clasps, plus a horizontal strap with its clasps to hide!
My friend says don't worry at all, as all the women who have "outed" her as a bra wearer have been fascinated by the extra strap and have asked for more details. I must say that discussing bra strap problems with other women would be an interesting & rather sexy experience!