Connect backside of mesh to form a cylinder

I am planning to make a parametric bike handle which uses a 3d scanned mesh, I already got half of the mesh which should be used for your fingers apart but I am now running into the problem of not knowing how to connect the outer points to form the back side into a cylinder.

What would be the best way for this, I haven’t used grasshopper in a while so all knowledge is way off. I would love to hear how you guys would solve this, I don’t expect anyone to make a working script for me because I won’t learn much more. The ‘CDDM Steff handvat’ is the stl used in this file.

outline curves grasshopper.gh (7.3 KB)
outline curves rhino.3dm (2.1 MB)
gefixt CDDM Steff handvat.stl (17.8 MB)


bar v0.gh (41.4 KB)