I use forms to bend wood for other things beside bows... The biggest factor for bow tips is going to be the radius of curvature, and whether you can get the woods you want to use, at the thickness you need, to make that degree of bend. I would say that builders start with art -- oh that's a sweet curve. And progress by experience to science - dang wood just doesn't want to make that tight bend!
It's also going to make a difference if you are bending the tips of a self bow; or creating curved siyahs which are glued onto the ends of the limbs of a Steppe type bow.