Hello, Luca, and welcome.
As it happens there is a group here trying to come up with standards for the same thing! We have made some maps in the past, and I will see if I can get you some links.
What we have found generally speaking is that it is better NOT to print Braille since it tends to clutter things up, and instead to have a separate key that ties together textures and braille.
You can read more about the big picture of our project, and some history, at
this link.
And specifically our thoughts about 3D printing Braille
at this link.
Let us know if you have more questions after you've had a look at those!
-Joan Horvath
www.nonscriptum.com