This is probably not very helpful, but when I went shirtless for a cosplay, I straight up made a full prosthetic chest out of foam, lycra spandex, and liquid latex.
Cosplays for 2016-17:
Hawke - Dragon Age (100%)
Obi-Wan Kenobi - Star Wars (Planned)
Padme Amidala (Loyalist Committee Gown) - Star Wars (Planned)
Eowyn - Lord of the Rings (Planned)