Matt,

what I am saying is that so far it looks like the spi is faster on a windward/leeward course.
You have got to have _some_ rules for measuring sailarea, and there are limitations to the geometry of a hooter. I.e. you dont want the same amount of leech area (shoulder). But a hooter would measure in under the Tornado rules. So far, we have not seen any boats use a similar sail in competition. Reason is quite clear, the spi has a better downwind VMG, and the hooter can only be used upwind in light conditions. Most Tornado events dont have predominantly light winds.
The hooter also adds windage (I dont know if it adds more than a snuffer+halyard, but I think so). It also adds weight aloft, and I think the snuffer systems we have today are more robust.

For distance racing, or enjoying myself on a boat, I would be very happy with a hooter.