They used to be outdoor ? If yes you can put them back out in the wild, if you keep them inside be sure to respect the 12/12 and remember NO LIGTH IN. As for the yeild that is a really good question, remember they will losse 3/4 of the weight in the process. I have not idea how big they are, try to take a picture with a common object (lighter, Smoke pack or even a rule). I'm sticking around, waitting to see it.