Thanks!
As for ratings, the answer is yes to educated guess and yes to formulas. I know that does not tell you much. lol
I have developed formulas over the years which are based on individual stats and team stats. The formulas differ by position to either give me overall ratings, or specific ratings. I also use my general football knowledge and knowledge of the players I am creating to pick up where formulas are not possible.
Of course the other part of all of this is understanding what Madden is capable of in terms of ratings, gameplay, and simming. I have done a lot of testing over the years as well as collaboration with folks here. I feel like I understand the ratings enough to manipulate them to give me the best results.