Adding my two cents. Sailing catamarans for 30yrs, current owner of an f16. Last weekend I got an opportunity to sail a F20c in 12-18 knots of breeze. The boat did jump out of the water on us a few times up wind. A fun experience but not a fast experience.
Downwind, single trap conditions, the curved boards created a special ride. The boat was not foiled up out of the water, but from the dagger board well to the bow she was clear of the water. The speed was in the 21 knot range. Steering got super sensitive because it felt like any turn of the tiller was not turning the hulls, but rather pivoting the boat on the curved board.
Overall I really enjoyed the curved board experience.
The phantom project might prove curved boards are outdated shortly?

Like Tim, I am short on money and time. But if my F16 manufacturer came out with a curved board package(kit) that was tested for the F16, granted non class legal, and the price was not ridiculous, I would go a head and make the change.

I am finding the biggest limitation with the F16 is the length. I solo the boat mainly, and really feel comfortable in pretty high wind conditions. It is the sea state, wave conditions that will cause me to back off sooner then I would like too. I wounder if the curved foils would improve the F16 ability to handle rougher wave conditions?