Hi Dean, and welcome! Mate, the most important factor when it comes to string alignment is that the string intersects the mid-line of the handle. The bend, wonk, and sway of the limbs otherwise does not much matter, within reason. To assess this for you properly we need a picture shot down the length of the stave with both limbs in view.
In any case, Osage bends relatively easily under heat. Like SlimBob said, you need to apply pressure to the section you want to straighten/bend whilst applying heat.
Additionally:
to prevent scorching, rub the area with grease or oil. I use raw linseed because my finish has a linseed oil base, but you can use canola, crisco, bacon grease etc.
heat the area gradually and evenly, moving the gun back and forth
heat the belly and sides only, not the back
And, don't worry, if you go too far, or not enough, it's easy enough to correct........
