Jake-
You mentioned something about being careful stressing the mast with your spin- is this because you risk inverting the mast with the spin if you don't trim it right? I also seem to remember some thread about the importance of keeping the mainsheet somewhat tight on spin runs to provide aft support of the mast (I would think for this reason). Should the spin be run to the very top of the mast?
I need lots of pictures to figure this out (brain has probs with thinking of all the ropes)