The SSVC film 'The Spin Explained' which was shown to all RAF students on the Tucano explains everything you need to know about the spin including the moments of inertia and B/A ratios.
It's available to purchase, but very expensive. It is however, very good. There is also a much older film "Spinning Modern Aircacraft' which was made in the 60's. It also is good, but not as good as the new film which has some pretty natty (for 1990!) computer graphics.