I do like Del. Most bows I rough out start with a front profile and more or less consistent thickness, or a slight thickness taper. That's just how it works out. So, when I start on the tiller tree, naturally, the inner limbs closest by the handle bend most/first. Just as if you bent an untillered 2x4.
As soon as I have that initial bending balanced between each limb (and the whole rest of both limbs almost not bending at all) I stop scraping near the fades, say that first 4" of limb length. The tips might be only moving 2" at that point, but I move on. By the time the tips are moving another two inches, the next , say 4" is bending, too. And so on. You could mark it with crayon to remind yourself to stay out. Then I chase that amount of bend out along the limbs.
If you are taking too much off at the fades, use a crayon to mark either what you want to stay out of, or what you want to scrape away, until you get the eye for it, and the feel.