Hello Hakan,
There is one very important point you did not mention. 1. The price of the Tornado just went up $5,000 plus US dallars. The boat is now a 30,000 dollar boat instead of a 25,000 dollar boat.
2. The weight of the carbon mast will not be 10kg lighter than the aluminum mast. Maybe a 5kg reduction is possible. If the new carbon mast is made to the same section as the present aluminum mast, it will be very very stiff. This means a new mainsail luff curve is required with much less curvature will have to be developed for the carbon mast and here goes the $$$$, dollars, running away again. Also the stiff carbon mast with reduced bend will make sails less versitile. Now the Tornado sailors will need light wind sails, medium wind sails and strong wind sails; the $$$$, dollars run away again.
3. The reason masts of any material bend in an S shape with spinnaker up is that the spinnaker hounds is too high above the main hounds, too much cantilever. Lower the spinnaker hounds is one solution. Another very simple and inexpensive solution is "back stays". Then you might as well go masthead with the spinnaker.
4. The present aluminum Tornado mast does have very little structural margin with the spinnaker and double trapeze. This is no surprise. A slightly larger aluminum mast section would be one answer. The cost of the new extrusion die equals the cost of one carbon mast.
Summary: What it comes down to is the Tornado class wants a carbon mast no matter what. To have it bend properly and have a thick enough wall so that the new mast does not have local buckling problems, the carbon mast section MUST BE SMALLER with a thicker wall. Then the class can have a mast that is bendy as the present aluminum mast and is tough at the same time with a reasonable wall thickness. The new smaller section carbon mast just made several hundred Tornado masts, maybe thousands, of aluminum Tornado masts not competitive. For a class to go from an aluminum mast to a carbon mast is one tough question. It has major impacts on many facets about the boat. It is not nearly as simple as "substitute carbon for aluminum and save 40% in mast weight and go for it".
Good Luck,
Bill