Think about that. If you brace early, very heavy, lots of belly wood ends up on the floor. If anything has taken set, it's been removed. As you remove that wood you lighten the load as you go, so less strain on the wood, less set. Getting a string on it early means you can get the brace profile dialed in way early. Once that brace profile is right, the rest is dialing in minor adjustments as you go. Since your still heavy, a good bit of wood will still be removed. Any damaged wood ends up on the floor. I know this to be true. My bows as a rule hold their profiles well. I am the first to tell people that in this craft there are many ways to skin that cat, and I don't claim my way is the right way. It's just my way. But I will claim that my way works.
Bryce is right. Good floor tiller is critical.