I've put together a document which I hope captures the most recent discussions I've had, particularly those in Barcelona. Commenting should be open to anyone, so please feel free to weigh in before too much code is written. ;) https://docs.google.com/document/d/1nJuG1KHtzU99HU9BK9Qxoo1ib9VXf2vwVuHzVQc_lKg/edit?usp=sharing