Hey guys, a young beginner here with a question regarding sail design.

I've attached a graph of an RSX 520 mast bend under different loads, but this question applies to all (most?) windsurf sails.
As you can see there is a big difference between the mast-bend of a rigged sail and the IMCS defining ~30kg load @50% of mast length.

If I were to make a sail from scratch - only having the mast, how would I go about defining the bend of the mast under which ill design my sail ? If I define my draft amount via additional luff curve and my draft posit. via broadseam for the ~30kg load as displayed, am I missing out on some black magic that is achieved by designing the sail around a bigger bend, and if so, is there an optimal bend ? Thanks.