Sounds like your having fun. Compost, I hear, should be thermally maintained, however castings need not be. Black may indicate an anaerobic nature. Worms can double in mass every 2 months and will process cardboard, paper or yard waste and do not need to be thermally done. Jeff Lowenfel has a book Teaming with microbes that is a great resource for such things microbial. The leaves do seem to grow many times the size in some cases