for a 32 back it’s about 120cc per cup size, i thyink you have enough size to get away with the 330, and it’s really only half a cup size bigger anayway.
Listen to your surgeon though as they will be able to tell if there is a chance of rippling or them looking fake.
I had 340cc froma 32b (empty) to a 32DD at the mo, so it’s quite a jump!