Some of the old Ionic Volute methods produced gaps between some of the quarter circles, which is often not mentioned.

In the 2005 book, The Classical Orders of Architecture, by Robert Chitham, the simple method of Chambers is given.
The Chambers method uses quarter circle arcs, without gaps. The results seem superior.

Surprisingly, it seems that a legitimate pdf of the book is available:
https://archive.org/details/The_Classical_Orders_of_Architecture_2nd_ed_R._Chitham_Arch._Press_2005_BBS

https://archive.org/download/The_Classical_Orders_of_Architecture_2nd_ed_R._Chitham_Arch._Press_2005_BBS/The_Classical_Orders_of_Architecture_2nd_ed_R._Chitham_Arch._Press_2005_BBS.pdf (free)

For the offset curve, called a "fillet," I used a sweep with pointy end, rather than finish laying out a second set of cyan points in the eye and drawing more arcs,
which are slightly different than the sweep.

- B