Summary

This is a modified version of the geometry used in DoubleTwistVase2 (https://www.thingiverse.com/thing:2412366), but I used only a single twist to eliminate problems with overlapping shells. This part printed in 21 hours using a layer height of 0.200 mm and a print speed of 100 mm/sec.

The issue of overlapping shells is complex, but there are some tricks for dealing with them. See this blog page for more info if you are interested: http://birkbinnard.com/blog/do-the-twist/