Long ago i used to model in modo with the aid of a pluging called Etrea Super Aligner. A collection of very handy scripts to quickly straighten out vertices. I have not found scripts that can do this in C4D, yet. Anyone knows of scripts that can do this:
You need a rail spline, and to enable that option in the sweep properties. A rail is copy of your coil spline, positioned directly 'in front' of your sweep to give an up-vector for the profile. See the help.