@ps23Rick
During sleep my mind often gets ‘raked over’, like gathering leaves into a pile to reveal what may be lying on the ground.
This is an altered Base Profile used in used in my ScreenShot above, with Sketch > Offset > Loop applied and of course you can set the Offset measurement as required, The Height of the Inner Body is 300mm and the Outer Body 305mm, in this case:
The beauty of this is the accuracy of the result.
However as can bee seen the ratio is close to basic, and height increase becomes a significant factor to consider. The Draft Angle refuses to be set beyond, as yet, undefined limits.
So Experiment is the Key to success.
Credit is due to @GiddsV in:
https://discourse.shapr3d.com/t/why-i-can-t-shell-this-loft-object-please-help/6621/7
For introducing this possibility to me.