Compound radius

[Heft]

I'm just wondering how Warmoth measures its radius. I've heard from some sites that its from the nut to the last fret (is this the case?) However I know Warmoth makes many neck lengths.
I want to know this because I would like to match my bridge to my neck taper and choose a neck radius accordingly.

 

[stratamania]

https://warmoth.com/guitar-neck-fretboard-radius

A 10 - 16" for example would end up with a bridge radius of around 18"... a 9.5 - 14" would end up with a bridge radius of around 16".