Neither of those methods don't create a good curvature. In simple bake with custome vertex normals a result is dont correct. I expect to see only white gradient without hardedges were noticable. The only way to create curvature from OSNM is to blur it out in 3dCoat (automatically) or Mudbox (manually) to create…
I've done it ok. Just make sure your model is smoothed when you export it. Put it in both the high and the low inputs in xNorlmal and bake your curvature from there. You might need to tweak the settings a,little but it works. There's another option where you create a n object space normal and use that to create a curvature…