Made changes to get rid of CGAL errors. This model does render slowly, but I haven't seen the errors using the thingiverse customizer or openscad 2019.05.
Also, added 1x, 2x, and 3x nozzle size (0.4mm) to wall thickness of the ribbons.
This design can have a lot of stringing from filament variations in diameter and slicer settings being a little off. The picture of the print I made was using a very cheap PLA filament with variations of 1.7mm - 1.74mm in diameter. It had a fair amount of stringing that was cleared post printing.
The STL file included was created with the following parameters:
9 - ribbons
double helix - spiral type
70mm - diameter
0.8mm - wall thickness
3mm - spiral width.
3D Filament PLA PLA