Edit Rating Weights
How to reach it
In the Games & Emulation Main Screen in the Rating tab (bottom right) click the Edit weights link.
How it works
Select the Rating Category and type a number between 1 and 99 in the Weight column.
By default, every Rating Category is weighted with 1, which means that every rating category is treated equal in the calculation of the total Rating. If a Rating Category A is twice as high than a Rating Category B, A would count twice as much towards the total Rating than B.