This may be a bit off topic, because I haven't really read the whole thread. I'm not really a theory kind of guy, I prefer to sail more and think about it less. And i'd tried to sail without a fin this summer... and with the correct stance, the board was the same as if it had a fin, it is just a bit more difficult to do carve gybes and not to spin out. As I said, you just need the correct stance (weight on the front foot and the mastfoot/harness lines). Having no fin is great for FREESTYLE though =p
Don't think it's that far out of the box...
All the best