I second the things mentioned here :3.
I would recommend going for a compression shirt. I'm also a large chested girl, and have used ace bandages and I always run into issues. I have trouble breathing, and ace bandages will tighten over time so it can become dangerous (I've actually heard of people accidentally breaking ribs this way x.x...). So compression shirts are worth the money and much more effective :3.
Cosplays in progress:
Demon form Rin - 50%
Battletorn Levi - 80%
Interrogation Levi - 70%
Angel form Stocking - 50%
Props in progress :
3D Maneuver Gear
Rin's Katana 30% *eventually LED
Stocking's sword 30% *eventually LED