When I made the sister size chart, I used this page from Wikipedia as a basis for the left side with the cup volumes. It uses a mathematical formula, which assumes that the breasts are a half-sphere shape.
However, how many breasts do you know that are a half-sphere shape? Not many that I can think of. Is there a better way to measure volume?
Water displacement would be the somewhat obvious choice here. It's great for measuring volumes that are not uniform in shape. My question is, how would it work? Wambrita tried it a few times and it seemed to help her discover how her breast shape changed over time.
Knowing your breast volume is super helpful as an additional piece of information when sizing. Underbust and bust measurements are a good starting point, but don't tell you everything. Anyone else want to try a water displacement experiment? Let me know how it goes!