I mean, this is my sort of thing and these .sav files are fairly forgiving and fun to rewrite.
... but you have to be able to read the data in the first place. it took me about eight hours to understand the format completely.
even now the game thinks that every female relation is "my sister"
anyway, you can just open save files in notepad. when you "save as", set to "any file type" and utf-8 format.
some easy changes are to give yourself more gold and other resources. I mostly used it to make all the women tall and to give my character a mother.
have fun, I am happy to share my knowledge if there are specific questions.