My favorite sport bra ever is a Moving Comfort "Fiona". It's wicking and reins my 36DD's in comfortably. I am not squashed flat and while there's movement I don't bounce. It also has adjustable straps. They are velcro so I don't know how they'd hold under water-you might have to fit and sew them permanently?
That said, it's not a swim top. I'd say to try your local tri outfitter but the best one around here is run by men who do an amazing job of fitting shoes but have not a clue about bras. Most of the shops just assumed I'd be a large which is far too large in the band.
For the info I also liked title9 but I went local to make sure I got the fit I wanted.
I used to have an open mind but my brains kept falling out.