I think that the initial bend depends a lot on starting thickness taper. If you start with an even thickness along the whole limb, it’ll almost always have too much bend near the handle. After building a lot of bows, you start to find out what thickness taper is close to the type of bend you want. Hard part is gaining that experience if you haven’t built many bows as people don’t usually post the limb thickness of their bows. After I made a few dozen, I measured the thickness of the ones I liked, they usually ended up close to the same thickness regardless of wood species.