I have always bugged by the location and name of the locus slavi and campus latgallia or whatever the names of those two settlements were. So here you go.
Just unzip and paste in your RTW folder.
Changes:
*the location of the settlement now formerly known as vicus slavi or something, changed to more correctly fit the ancient population centres in the regions where balts lived;
*name changed to "campus latgallia";
*the name of the former "campus latgallia" swapped to more accurately represent the ethnic distribution.
I will add more stuff later.