With respect to my design I can say the following.

If indeed Gato build his 4mm ply + glassed over hulled platform at 52 kg including a 6 kg mast then my basic design can be build for about 55 kg, both ready to sail. That is using the same platform but with a 6.5 kg unstayed mast, 1.5 kg support tubes and 1 kg of additional reinforcments in the hulls (an extra bulkhead and some local thickening of the skin near the load points.

Note how a set of 4 mm stainless steel stays are already 1 kg in total for a F12. My unstayed setup doesn't really have a weight problem. Although I would like enough volume/size in the hulls to carry a 90 kg adult with camping gear or two kids sailing together, I also perfer to use larger beams as to avoid the need for a dolphinstriker in order to reduce (labour) cost further and make transport easier (slide and lay-up the boat up on its two beam over two planks fitted to any trailer or roofrack)

So personally for my design I wouldn't mind 55 kg or even 50 kg as I believe 5 kg difference in weight is impossible to note on the water. However, I do envision that any cheap commercial production of F12's will have needs that may wel conflict with such a low ready to sail weight. I envision that for succes a la laser radial or optimist we need such commercial builders and still keep the retail price of a F12 below 4000 bucks. That doesn't leave much margin for labour costs or high quality laminate work.

So I'm arguing for a rather "high" ready to sail weight not to favour my own design but rather for the future growth of the class and indeed to have an optimal chance in achieving the ultimate goals set for this new class. If it were only up to myself and my own use then I would vote 50 kg in within a bloody second. I'm never going to be a competitive sailor in this class at 90 kg anyway !

I wanted to have this be clear.

Wouter