Back from skiiing which was very hard work as I am having great trouble turning right. Have to try again next year.
At least I got some reading done. The Lewis book was really helpful as it sought to explain the medieval workview. You need to have this in mind when reading old literature and also understand how it fitted together. The key point is that the way they saw the world was entirely rational in their own terms and consistent with what they knew. It actually made a lot more sense than the purposeless and blind universe of modern science. The book contained lots of useful stuff for putting Copernicus in context even though it is largely about literature.
Finally found out where the analogy of the net that can't catch small fish comes from: it isn't Wittgenstein but Arthur Eddington from the Philosophy of Physical Science (at least according to this week's TLS). I need to get an exact reference for my Dialogue on Natural Theology.