Guitar neck taper?

Don’t ask why, but I need to model a guitar neck.

The skinny end’s arc (official luthier jargon) is NOT proportional to the fat end’s arc, so this scaling business is not going to work.
Below image shows the length and the skinny end arc that this thing needs to taper to…
I was thinking some type of Loft command?
Any ideas?

GIF 3-10-2020 7-18-27 PM


I’ve certainly heard of that plug-in, but didn’t realize it was that simple to use.
Thank you!