I have attached images of my screen from rhino and GH.  Im trying to have control of this surface so that I can move the edges in a clean way without having to manually rebuild the surface every time.

Right now I would like to be able to snap the edge that is closet to the vertical green line to that line.  I am having the hardest time figuring this out.  I am still pretty much a novice with all this.

Im sure this isn't super clear if there is anything else I can provide please let me know.  

Thanks

Stanley