I haven't done it.
Are you familiar with the work of
Giuseppe Ottusi, a former racer who did this type of work 40-50 years ago? As I understand it, the Unica nitor saddle was based on the shape of his reworked Brooks saddles.
As I learn to recover Brooks saddles, I am trying to give them a Unicanitor-like shape, rather than the typical Brooks shape. I have some photos I will share as soon as I can find them.