should the hard chines be left on a stripper as an angle, such as the Petrel or do they get rounded over when you sand the hull.

I don't know how much rounding you are considering, but (to keep the wood thickness consistent) my inclination would be to do any major rounding on the forms before stripping.
Of course, if you are joining hull & deck at that point you can use a sheer clamp (wood backer) at the 'corner' to take away structural concerns with sanding the outside (within limits...)