Shimano does an impressive job documenting all of the Alfine Di2 components and making it readily available through the internet.  Even so, I had a hard time finding answers to a variety of questions before I took the plunge and just purchased the stuff.  To be fair, many of these questions come from the fringes of trying to adapt to a recumbent trike a system that is designed for upright bikes.  Now I know the answers to most of my burning questions, and so do you.