I have not seen a guide. All I know is the personality traits do effect some what on how they handle matches. How much personality traits effect it I don't know. I do know when it comes to my created wrestler I started everything out on 0 and through out the universe his personality traits changed based on the way I played with my character.
FYI the personality traits that you edit in universe will not carry over to a new one. I found that out yesterday. I reset my universe and I also tried creating a new one and the personality traits don't carry over if i edit them through roster before starting universe. So if you reset or restart a universe you have to redo the personality traits.
Some more info. If you start a new universe or reset the one you have when it comes to attributes and payback bages you can carry those over by going to moveset and opening each character that is all ready edited in those 2 areas then just hit save without changing anything and it will give you the option to save it to your universe roster.