What size implant would give me a D/DD cup? (Photo)

It's extremely important to me I'm able to wear the shirts/blouses I currently own. Most are size S/M. So the ending cup size id like to be at is a double D. I'm currently a big B/small C. And was initially thinking 425/450cc... But now I'm thinking that will put me at a triple D, are there any professional opinions out there of a CC range that will keep me at the D/DD bra size ? Thank you!