A basic rule of thumb that most of us use is you loose 30-40% of the raw weight vs. finished weight. It will varry a bit from piece to piece depending on the amount of fat and connective tissues present.Is there a semi guide on weight loss? as an estimate I started with a 6.3lb boston butt and ended with about 20 percent weight loss, the bone was kinda large (fat dog was happy). The pictures of the whole roast (butt) didn't give it justice, it didn't look shrunk.
Tut