Fit & Sizing
Start with the loosest hook on your bra clasp. Your bra bands become looser with wear and wash - tighten if necessary for a good fit.
Your bra band should be horizontal, not pulling upwards. Loosen your straps such that the height of your fingers can run between your strap and shoulder comfortably.
If you experience a gap in your bra cup, try a fuller cup like the Circe Bra. It is a lifesaver for this writer - even when you wear her strapless.
Sister Size
You have more than one size option when it comes to shopping for bras. If you've been wearing 75A, try a 70B. For 70C, your sister size will be 75B.
The concept: up on your band, down on your cup (and vice versa). The cup volume remains consistent, but the size label and fit shifts.
We find sister sizing helpful especially if you've been hitting the gym. Your beautiful lat growth may mean your bands feel tighter - try increasing the band size and lowering your cup size instead.