Ok Wouter, you're right.

I've done some back of the envolope type calculations. I came up with a maximum of 3% weight reduction through pre-bend. The result will vary according to the specific geometry. You can take some weight out of the main beam, but much of that reduction is cancelled out by the extra weight you have to put into the dolphin striker.

Of course, if you downsize to take advantage of the added strength, you will lose some stiffness.

Interestingly, if you could measure in with highly pre-bent beams and then flatten them out on the water, you could effectively get some hull cant.