I am  trying to model a volute or monkey tail staircase handrail termination.

Obviously I get rebuild errors in the test part i have attempted, as it can't fold it in on itself, my questions is how would i model this if I cant just extrude the profile along the path? eventually I will be wanting to use a traditional wooden profile handrail. I understand the geometry plotting out the path just not the method in solidworks.

I originally used sketchup to model this which ironically this was relatively straight forward extrude and it just folded it self in, i just wanted to draw the whole thing in solidworks now.

thanks