my instructor did a set up with us with every new segment, and kept in mind the different positions that we would have to be in. Try getting asking about ideals set up if you haven't already done so.
Love the spinning classes though, they really helped me out with my climbing and breathing techniques, and kept me in shape for the spring. Great way to spend the winter though, especially in Ottawa, when the only riding I can continue is urban when the roads and "stunts" are cleared.