Using my familiarity with the generals and what their overall attribute levels should be (given that CA used the novel as a reference), I've tried to alter the various attributes of Zhao Yun and Gongsun Zan using rPFM (in 'database/character_generations' or some such) and add in some of my own custom characters. It seems though, that if I change the values of the fields in the columns with various large numbers in them, there is no discernable effect or the game crashes. Interestingly, if I set the value to a number well outside the range of what currently exists, the general's attributes have a question mark next to them in-game.

Some huh?