I’m a little stuck right now on this problem and I’m not seeing an easy or efficient solution to the problem.
I basically create a face and a path and use the followme method to extrude along the path. The original face remains and so I am able to grab that face from its original handle and manipulate its vertices as required.
The hard problem is how to acquire the vertices of the face at the other end of the solid (at the end of the extrusion). My proposed algorithm is to check all of the faces of the group and compare the area of each with the original face, if they match then it should be the opposite face however this method is not totally 100% bullet proof.