Hi Marco,

When I model a ring I use 95% flow function.
I think it's the easiest technic to have texturing and easy sizable ring

Flow with surfaces or Flow with curves

It depends of result you want to have.

Here I show you different possibilities on simple samples :





I use cylinders, circles, extruded helix, flaated helix, cutted cylinder.

I use the "object library" plugin to have always this shapes in an easy access.



If your base object is "filet able", you have no problem... to have a fileted final solid.