I second this question. As an engineer I share your interests even though I may see the problem from a slightly different point of view. From my experience, a heavy wing (moment of inertia) and an airfoil with much hysteresis, beside a tip-stall prone planform, make for nasty spin exit. I feel affirmed since [link=http://www.av8n.com/how/htm/spins.html#sec-spin-recovery]Denker[/link] refers to losing vertical and roll damping in spin. But [link=http://ntrs.nasa.gov/search.jsp?R=227470&id=1&as=false&or=true&qs=Ntt%3 Dd-6575%26Ntk%3Dall%26Ntx%3Dmode%2Bmatchall%26Ns%3DHa rvestDate%257c1%26N%3D0]this[/link] NASA report may give an authoritative overview.

May I in turn ask another, relating question? Do you all use ailerons in spins? A while ago I learned that it's customary using ailerons for snap rolls since maybe the 1970s. But I thought spins are still done the "pure", old-school way, except with the modern aerobats with special airfoils. And by the way, did you ever spin your Skylane?

Edit: Link was wrong, if it still doesn't work search for NASA-TN-D-6575.