Hi,

I've never used it, but can you use a curve on suface for the original curve? If so, it might pull the curve normal from the suface normal which will always face out. So try taking your curve, extrude it a bit, and then grab an isoparm, or intersect a plane to make a cos and see if the script takes that.

This works well for a spline ik curve so the joints don't flip around.

sj