Wouter,

The Texel Rule seems really silly.

You wrote:
< I'll give you a hint : "11 % performance loss with respect to the same design when fitted WITH a jib">

As you know, BIMARE has been building only unirigged cat since 30 years.
A sloop rigged BIM 16 exists only in the mind of the Texel measurer.
I am afraid that he is often drunk.