Pre-bend is a function of spreader rake and diamond tension. Less spreader rake and tension and the mast will be slower to react to gusts. More rake and tension and the mast will depower faster when you pull on downhaul or even when you go out on trapeeze. As always it is a compromise, but if you are racing it is critical to get a luff curve matching the bending characteristica of your mast. You can adjust it a bit with pre-bend, but getting the sweet spot where the mast do the work for you and depower in gusts is harder then.

I always have to remind myself that more power comes at the cost of more drag, it will not always be faster to have more power!